From 039ea70edfc7b24e5221d9e0cb59d3a5aeb36b99 Mon Sep 17 00:00:00 2001
From: CNWei <t6g888@163.com>
Date: Sat, 19 Sep 2026 23:17:36 +0800
Subject: [PATCH] =?UTF-8?q?feat:=20=E5=AE=9E=E7=8E=B0=E5=AF=BC=E8=88=AA?=
 =?UTF-8?q?=E9=A1=B5=E5=9F=BA=E7=A1=80=E5=8A=9F=E8=83=BD?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

- 添加导航条目和分类数据模型
- 实现导航卡片网格展示
- 支持点击卡片打开链接
- 添加主题样式（渐变色、卡片阴影）
- 区分系统默认和自定义条目
- 添加分类统计信息"
---
 backend/README.md                             |  39 +-
 backend/data/nav.json                         | 148 +++
 backend/data/site.json                        |   4 -
 backend/data/system-categories.json           |  74 --
 backend/data/system-sites.json                |  62 --
 backend/data/user-categories.json             |  47 -
 backend/data/user-sites.json                  |  14 -
 backend/src/api.rs                            |  10 +-
 backend/src/model.rs                          | 107 +-
 backend/src/store.rs                          | 987 +++++++++---------
 docs/backend-site-schema.md                   |  19 +-
 docs/frontend-architecture.md                 |  24 +-
 docs/submit-site-form.md                      | 116 --
 frontend/README.md                            |  16 +-
 frontend/lib/core/constants/app_sizes.dart    |  27 -
 .../home/data/http_home_repository.dart       |   1 +
 .../features/home/data/mock_home_data.dart    |   1 +
 .../home/domain/models/home_data.dart         |   6 +
 .../home/presentation/pages/home_page.dart    | 107 +-
 .../presentation/widgets/confirm_dialog.dart  |  91 --
 .../presentation/widgets/dialog_buttons.dart  | 117 ---
 .../home/presentation/widgets/link_card.dart  | 160 +--
 .../widgets/link_section_view.dart            |  15 +-
 .../widgets/site_form_dialog.dart             | 757 --------------
 .../home/presentation/home_page_test.dart     | 195 +---
 .../presentation/site_form_dialog_test.dart   | 235 -----
 26 files changed, 796 insertions(+), 2583 deletions(-)
 create mode 100644 backend/data/nav.json
 delete mode 100644 backend/data/site.json
 delete mode 100644 backend/data/system-categories.json
 delete mode 100644 backend/data/system-sites.json
 delete mode 100644 backend/data/user-categories.json
 delete mode 100644 backend/data/user-sites.json
 delete mode 100644 docs/submit-site-form.md
 delete mode 100644 frontend/lib/features/home/presentation/widgets/confirm_dialog.dart
 delete mode 100644 frontend/lib/features/home/presentation/widgets/dialog_buttons.dart
 delete mode 100644 frontend/lib/features/home/presentation/widgets/site_form_dialog.dart
 delete mode 100644 frontend/test/features/home/presentation/site_form_dialog_test.dart

diff --git a/backend/README.md b/backend/README.md
index 61a9933..1668252 100644
--- a/backend/README.md
+++ b/backend/README.md
@@ -27,22 +27,39 @@ cargo clippy --all-targets
 
 ```
 data/
-├── site.json                # 站点名与搜索框提示，只读
-├── system-categories.json   # 内置分组，只读，自己手写维护
-├── system-sites.json        # 内置网站，只读
-├── user-categories.json     # 提交时创建的分组，自动写
-└── user-sites.json          # 提交 / 推送的网站，自动写
+└── nav.json                 # 站点信息 + 分组结构 + 网站，全在这一份文档里
+```
+
+侧栏的结构和网站数据放在同一个文件里，删除网站和「它的分组要不要一起清掉」
+是同一次写入完成的——不会出现网站没了、侧栏还挂着一个空分组的中间状态。
+写盘用「先写临时文件再改名」，不会因为写到一半断电把文件写坏。
+
+```json
+{
+  "site": { "name": "Suxing Nav", "searchHint": "…", "submitUrl": "https://mattermost…" },
+  "groups": [
+    {
+      "id": "common", "title": "常用推荐", "source": "system", "order": 10,
+      "createdAt": "…", "updatedAt": "…",
+      "sites": [ { "id": "github", "title": "GitHub", "url": "…", "source": "system", … } ],
+      "children": []
+    }
+  ]
+}
 ```
 
 启动时会自检，任何一条不通过就直接退出（避免带着坏数据继续跑）：
 
-- `system-*.json` 里的 `source` 必须全是 `system`，`user-*.json` 里必须全不是；
-- 网站 id、分组 id 不能重复；
-- 每个网站的 `categoryId` 必须存在，且**内置网站只能挂在内置分组下、
-  提交的网站只能挂在用户分组下**；
-- 分组的 `parentId` 必须存在、必须是一级分组（最多两级），也不能指向自己。
+- `site.name` 不能为空；
+- 分组 id、网站 id 不能重复（两者共用一个 id 空间）；
+- 分组最多两级；
+- **内置分组下只能放内置网站，用户分组下只能放用户网站**。
 
-写盘用「先写临时文件再改名」，不会因为写到一半断电把文件写坏。
+### 内置与用户数据怎么隔离
+
+以前是「系统文件只读、用户文件可写」，现在合并成一个文件，隔离改成靠 `source`：
+写操作只会碰 `source != system` 的分组和网站，内置的那部分只会被原样读出来再写回去。
+启动自检会拦住「手改 JSON 把内置网站标成用户来源」这类越权。
 
 ## 接口
 
diff --git a/backend/data/nav.json b/backend/data/nav.json
new file mode 100644
index 0000000..d063806
--- /dev/null
+++ b/backend/data/nav.json
@@ -0,0 +1,148 @@
+{
+  "site": {
+    "name": "Suxing Nav",
+    "searchHint": "输入关键字搜索全网资源...",
+    "submitUrl": "https://mattermost.example.com"
+  },
+  "groups": [
+    {
+      "id": "common",
+      "title": "常用推荐",
+      "source": "system",
+      "order": 10,
+      "createdAt": "2026-09-13T10:29:48Z",
+      "updatedAt": "2026-09-13T10:29:48Z",
+      "sites": [
+        {
+          "id": "github",
+          "title": "GitHub",
+          "url": "https://github.com",
+          "description": "代码托管与开源社区",
+          "source": "system",
+          "order": 10,
+          "createdAt": "2026-09-13T10:29:48Z",
+          "updatedAt": "2026-09-13T10:29:48Z",
+          "submittedBy": ""
+        },
+        {
+          "id": "zhihu",
+          "title": "知乎",
+          "url": "https://www.zhihu.com",
+          "description": "深度内容问答社区",
+          "source": "system",
+          "order": 20,
+          "createdAt": "2026-09-13T10:29:48Z",
+          "updatedAt": "2026-09-13T10:29:48Z",
+          "submittedBy": ""
+        },
+        {
+          "id": "bilibili",
+          "title": "哔哩哔哩",
+          "url": "https://www.bilibili.com",
+          "description": "弹幕视频分享网站",
+          "source": "system",
+          "order": 30,
+          "createdAt": "2026-09-13T10:29:48Z",
+          "updatedAt": "2026-09-13T10:29:48Z",
+          "submittedBy": ""
+        }
+      ],
+      "children": []
+    },
+    {
+      "id": "materials",
+      "title": "素材资源",
+      "source": "system",
+      "order": 20,
+      "createdAt": "2026-09-13T10:29:48Z",
+      "updatedAt": "2026-09-13T10:29:48Z",
+      "sites": [],
+      "children": [
+        {
+          "id": "design",
+          "title": "UI 设计",
+          "source": "system",
+          "order": 10,
+          "createdAt": "2026-09-13T10:29:48Z",
+          "updatedAt": "2026-09-13T10:29:48Z",
+          "sites": [
+            {
+              "id": "figma",
+              "title": "Figma",
+              "url": "https://www.figma.com",
+              "description": "协同界面设计工具",
+              "source": "system",
+              "order": 10,
+              "createdAt": "2026-09-13T10:29:48Z",
+              "updatedAt": "2026-09-13T10:29:48Z",
+              "submittedBy": ""
+            },
+            {
+              "id": "dribbble",
+              "title": "Dribbble",
+              "url": "https://dribbble.com",
+              "description": "全球设计作品分享社区",
+              "source": "system",
+              "order": 20,
+              "createdAt": "2026-09-13T10:29:48Z",
+              "updatedAt": "2026-09-13T10:29:48Z",
+              "submittedBy": ""
+            }
+          ],
+          "children": []
+        },
+        {
+          "id": "icon",
+          "title": "图标库",
+          "source": "system",
+          "order": 20,
+          "createdAt": "2026-09-13T10:29:48Z",
+          "updatedAt": "2026-09-13T10:29:48Z",
+          "sites": [],
+          "children": []
+        },
+        {
+          "id": "stock",
+          "title": "高清壁纸",
+          "source": "system",
+          "order": 30,
+          "createdAt": "2026-09-13T10:29:48Z",
+          "updatedAt": "2026-09-13T10:29:48Z",
+          "sites": [],
+          "children": []
+        }
+      ]
+    },
+    {
+      "id": "dev-tools",
+      "title": "开发工具",
+      "source": "system",
+      "order": 30,
+      "createdAt": "2026-09-13T10:29:48Z",
+      "updatedAt": "2026-09-13T10:29:48Z",
+      "sites": [],
+      "children": [
+        {
+          "id": "dev",
+          "title": "前端框架",
+          "source": "system",
+          "order": 10,
+          "createdAt": "2026-09-13T10:29:48Z",
+          "updatedAt": "2026-09-13T10:29:48Z",
+          "sites": [],
+          "children": []
+        },
+        {
+          "id": "api",
+          "title": "在线 API",
+          "source": "system",
+          "order": 20,
+          "createdAt": "2026-09-13T10:29:48Z",
+          "updatedAt": "2026-09-13T10:29:48Z",
+          "sites": [],
+          "children": []
+        }
+      ]
+    }
+  ]
+}
diff --git a/backend/data/site.json b/backend/data/site.json
deleted file mode 100644
index 4821e52..0000000
--- a/backend/data/site.json
+++ /dev/null
@@ -1,4 +0,0 @@
-{
-  "name": "Suxing Nav",
-  "searchHint": "输入关键字搜索全网资源..."
-}
diff --git a/backend/data/system-categories.json b/backend/data/system-categories.json
deleted file mode 100644
index b301c91..0000000
--- a/backend/data/system-categories.json
+++ /dev/null
@@ -1,74 +0,0 @@
-[
-  {
-    "id": "common",
-    "title": "常用推荐",
-    "parentId": "",
-    "source": "system",
-    "order": 10,
-    "createdAt": "2026-09-13T10:29:48Z",
-    "updatedAt": "2026-09-13T10:29:48Z"
-  },
-  {
-    "id": "materials",
-    "title": "素材资源",
-    "parentId": "",
-    "source": "system",
-    "order": 20,
-    "createdAt": "2026-09-13T10:29:48Z",
-    "updatedAt": "2026-09-13T10:29:48Z"
-  },
-  {
-    "id": "design",
-    "title": "UI 设计",
-    "parentId": "materials",
-    "source": "system",
-    "order": 10,
-    "createdAt": "2026-09-13T10:29:48Z",
-    "updatedAt": "2026-09-13T10:29:48Z"
-  },
-  {
-    "id": "icon",
-    "title": "图标库",
-    "parentId": "materials",
-    "source": "system",
-    "order": 20,
-    "createdAt": "2026-09-13T10:29:48Z",
-    "updatedAt": "2026-09-13T10:29:48Z"
-  },
-  {
-    "id": "stock",
-    "title": "高清壁纸",
-    "parentId": "materials",
-    "source": "system",
-    "order": 30,
-    "createdAt": "2026-09-13T10:29:48Z",
-    "updatedAt": "2026-09-13T10:29:48Z"
-  },
-  {
-    "id": "dev-tools",
-    "title": "开发工具",
-    "parentId": "",
-    "source": "system",
-    "order": 30,
-    "createdAt": "2026-09-13T10:29:48Z",
-    "updatedAt": "2026-09-13T10:29:48Z"
-  },
-  {
-    "id": "dev",
-    "title": "前端框架",
-    "parentId": "dev-tools",
-    "source": "system",
-    "order": 10,
-    "createdAt": "2026-09-13T10:29:48Z",
-    "updatedAt": "2026-09-13T10:29:48Z"
-  },
-  {
-    "id": "api",
-    "title": "在线 API",
-    "parentId": "dev-tools",
-    "source": "system",
-    "order": 20,
-    "createdAt": "2026-09-13T10:29:48Z",
-    "updatedAt": "2026-09-13T10:29:48Z"
-  }
-]
diff --git a/backend/data/system-sites.json b/backend/data/system-sites.json
deleted file mode 100644
index ae9b4df..0000000
--- a/backend/data/system-sites.json
+++ /dev/null
@@ -1,62 +0,0 @@
-[
-  {
-    "id": "github",
-    "title": "GitHub",
-    "url": "https://github.com",
-    "description": "代码托管与开源社区",
-    "categoryId": "common",
-    "source": "system",
-    "order": 10,
-    "createdAt": "2026-09-13T10:29:48Z",
-    "updatedAt": "2026-09-13T10:29:48Z",
-    "submittedBy": ""
-  },
-  {
-    "id": "zhihu",
-    "title": "知乎",
-    "url": "https://www.zhihu.com",
-    "description": "深度内容问答社区",
-    "categoryId": "common",
-    "source": "system",
-    "order": 20,
-    "createdAt": "2026-09-13T10:29:48Z",
-    "updatedAt": "2026-09-13T10:29:48Z",
-    "submittedBy": ""
-  },
-  {
-    "id": "bilibili",
-    "title": "哔哩哔哩",
-    "url": "https://www.bilibili.com",
-    "description": "弹幕视频分享网站",
-    "categoryId": "common",
-    "source": "system",
-    "order": 30,
-    "createdAt": "2026-09-13T10:29:48Z",
-    "updatedAt": "2026-09-13T10:29:48Z",
-    "submittedBy": ""
-  },
-  {
-    "id": "figma",
-    "title": "Figma",
-    "url": "https://www.figma.com",
-    "description": "协同界面设计工具",
-    "categoryId": "design",
-    "source": "system",
-    "order": 10,
-    "createdAt": "2026-09-13T10:29:48Z",
-    "updatedAt": "2026-09-13T10:29:48Z",
-    "submittedBy": ""
-  },
-  {
-    "id": "dribbble",
-    "title": "Dribbble",
-    "url": "https://dribbble.com",
-    "description": "全球设计作品分享社区",
-    "categoryId": "design",
-    "source": "system",
-    "order": 20,
-    "createdAt": "2026-09-13T10:29:48Z",
-    "updatedAt": "2026-09-13T10:29:48Z",
-    "submittedBy": ""
-  }
-]
diff --git a/backend/data/user-categories.json b/backend/data/user-categories.json
deleted file mode 100644
index a2cac7a..0000000
--- a/backend/data/user-categories.json
+++ /dev/null
@@ -1,47 +0,0 @@
-[
-  {
-    "id": "g-20260919-c8460f",
-    "title": "嗯嗯",
-    "parentId": "",
-    "source": "submission",
-    "order": 10,
-    "createdAt": "2026-09-19T13:30:25Z",
-    "updatedAt": "2026-09-19T13:30:25Z"
-  },
-  {
-    "id": "g-20260919-e78b21",
-    "title": "收拾收拾",
-    "parentId": "g-20260919-c8460f",
-    "source": "submission",
-    "order": 10,
-    "createdAt": "2026-09-19T13:32:03Z",
-    "updatedAt": "2026-09-19T13:32:03Z"
-  },
-  {
-    "id": "g-20260919-460478",
-    "title": "AI 工具",
-    "parentId": "",
-    "source": "submission",
-    "order": 20,
-    "createdAt": "2026-09-19T13:38:10Z",
-    "updatedAt": "2026-09-19T13:38:10Z"
-  },
-  {
-    "id": "g-20260919-6b3fa7",
-    "title": "模型社区",
-    "parentId": "g-20260919-460478",
-    "source": "submission",
-    "order": 10,
-    "createdAt": "2026-09-19T13:38:10Z",
-    "updatedAt": "2026-09-19T13:38:10Z"
-  },
-  {
-    "id": "g-20260919-91da17",
-    "title": "反反复复",
-    "parentId": "g-20260919-c8460f",
-    "source": "submission",
-    "order": 20,
-    "createdAt": "2026-09-19T13:39:53Z",
-    "updatedAt": "2026-09-19T13:39:53Z"
-  }
-]
diff --git a/backend/data/user-sites.json b/backend/data/user-sites.json
deleted file mode 100644
index a86ce40..0000000
--- a/backend/data/user-sites.json
+++ /dev/null
@@ -1,14 +0,0 @@
-[
-  {
-    "id": "s-20260919-f103b8",
-    "title": "Hugging Face",
-    "url": "https://huggingface.co",
-    "description": "开源模型与数据集社区",
-    "categoryId": "g-20260919-6b3fa7",
-    "source": "submission",
-    "order": 10,
-    "createdAt": "2026-09-19T13:38:10Z",
-    "updatedAt": "2026-09-19T13:38:10Z",
-    "submittedBy": "an@example.com"
-  }
-]
diff --git a/backend/src/api.rs b/backend/src/api.rs
index 4f156eb..265fe7b 100644
--- a/backend/src/api.rs
+++ b/backend/src/api.rs
@@ -9,9 +9,7 @@ use axum::{Json, Router};
 use tower_http::cors::CorsLayer;
 
 use crate::error::ApiError;
-use crate::model::{
-    CreateSiteRequest, NavResponse, Site, SiteView, Source, UpdateSiteRequest,
-};
+use crate::model::{CreateSiteRequest, NavResponse, SiteView, Source, UpdateSiteRequest};
 use crate::store::{Store, Summary};
 
 /// 全局状态。仓库放在互斥锁里：接口可能并发到达，而写文件必须串行。
@@ -81,7 +79,7 @@ async fn update_site(
 ) -> Result<Json<SiteView>, ApiError> {
     let mut store = lock(&state)?;
     let site = store.update(&id, &request)?;
-    Ok(Json(SiteView::from(site)))
+    Ok(Json(site))
 }
 
 async fn delete_site(
@@ -99,8 +97,8 @@ fn create(
     source: Source,
 ) -> Result<(StatusCode, Json<SiteView>), ApiError> {
     let mut store = lock(state)?;
-    let site: Site = store.create(&request, source)?;
-    Ok((StatusCode::CREATED, Json(SiteView::from(site))))
+    let site: SiteView = store.create(&request, source)?;
+    Ok((StatusCode::CREATED, Json(site)))
 }
 
 /// 取锁并把「锁被毒化」翻译成 500。
diff --git a/backend/src/model.rs b/backend/src/model.rs
index 0930d75..3bab5a0 100644
--- a/backend/src/model.rs
+++ b/backend/src/model.rs
@@ -1,11 +1,14 @@
-//! 落盘数据结构与对外返回结构。
+//! 数据结构：落盘的一棵树、对外返回的视图、以及请求入参。
+//!
+//! 落盘只有一个文件 `data/nav.json`：站点信息、分组 / 子分组、以及挂在分组下的
+//! 网站全在一份文档里。这样删除一个网站时，它的分组是否需要一起清掉，
+//! 和网站本身在同一次写入里完成，不会出现「网站没了、分组还空着」的中间状态。
 
 use serde::{Deserialize, Serialize};
 
 /// 数据来源。**唯一决定条目能不能被修改的字段。**
 ///
-/// 不额外存 `editable`：存两份状态迟早会不一致，比如手改 JSON 把 `source`
-/// 改成 `system`、`editable` 却还是 `true`。对外返回时按这里推导。
+/// 不额外存 `editable`：存两份状态迟早会不一致。对外返回时按这里推导。
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
 #[serde(rename_all = "lowercase")]
 pub enum Source {
@@ -24,14 +27,28 @@ impl Source {
     }
 }
 
-/// 一个网站条目。
+/// 站点级配置，由项目维护者手改。
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct SiteMeta {
+    /// 站点名，显示在侧栏顶部与浏览器标题。
+    pub name: String,
+    /// 搜索框占位文案。
+    #[serde(default)]
+    pub search_hint: String,
+    /// 「提交网站」跳转的地址（Mattermost 之类的收集入口）。
+    #[serde(default)]
+    pub submit_url: String,
+}
+
+/// 一个网站。
 ///
-/// 字段名在 JSON 里是 camelCase（和前端 Dart 的 `fromJson` 一致），
-/// 以后新增字段一律加 `#[serde(default)]`，老 JSON 文件仍然能读，不必写迁移。
+/// 网站不再自己记 `categoryId`——它就挂在某个分组的 `sites` 里，
+/// 归属关系由位置表达，删除分组时不会留下指向空处的引用。
 #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
 #[serde(rename_all = "camelCase")]
 pub struct Site {
-    /// 唯一标识，也是接口路径里的 id。
+    /// 唯一标识。
     pub id: String,
     /// 显示名称。前端取它的首字当图标。
     pub title: String,
@@ -39,8 +56,6 @@ pub struct Site {
     pub url: String,
     #[serde(default)]
     pub description: String,
-    /// 所属分组或子分组的 id。
-    pub category_id: String,
     pub source: Source,
     /// 同一分组内的排序值，小的在前。
     #[serde(default)]
@@ -53,71 +68,58 @@ pub struct Site {
 }
 
 impl Site {
-    /// 能不能被接口修改。
     pub fn is_editable(&self) -> bool {
         !self.source.is_system()
     }
 }
 
-/// 分组。`parent_id` 为空表示一级分组，不为空表示子分组。
+/// 一个分组：可以挂网站，也可以带子分组（层级最多两级）。
 #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
 #[serde(rename_all = "camelCase")]
-pub struct Category {
+pub struct Group {
     pub id: String,
     pub title: String,
-    #[serde(default)]
-    pub parent_id: String,
     pub source: Source,
     #[serde(default)]
     pub order: i32,
     pub created_at: String,
     pub updated_at: String,
+    /// 直接挂在这个分组下的网站。
+    #[serde(default)]
+    pub sites: Vec<Site>,
+    /// 子分组；只有一级分组会有。
+    #[serde(default)]
+    pub children: Vec<Group>,
 }
 
-impl Category {
-    /// 是不是一级分组。
-    pub fn is_root(&self) -> bool {
-        self.parent_id.is_empty()
-    }
-
-    /// 能不能被接口改动（提交时新建的分组才能被后续提交复用，内置分组只看不改）。
+impl Group {
     pub fn is_editable(&self) -> bool {
         !self.source.is_system()
     }
 }
 
-/// 对外返回的网站：在落盘结构上补一个推导出来的 `editable`。
+/// `data/nav.json` 的完整内容。
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct NavFile {
+    pub site: SiteMeta,
+    pub groups: Vec<Group>,
+}
+
+/// 对外返回的网站：补上它所属分组的 id 和推导出来的 `editable`。
 ///
-/// 这里存一份 `Site` 的拷贝而不是借用：接口层需要先把互斥锁放开、
-/// 再去序列化响应，借用会让生命周期绑死在锁上。
+/// `categoryId` 在落盘结构里已经由位置表达了，但接口仍然输出它——
+/// 前端编辑时要靠它反查出分组名。
 #[derive(Debug, Serialize)]
 #[serde(rename_all = "camelCase")]
 pub struct SiteView {
     #[serde(flatten)]
     pub site: Site,
-    /// 由 `source` 推导，不落盘。前端据此决定要不要显示编辑/删除入口。
+    pub category_id: String,
     pub editable: bool,
 }
 
-impl From<Site> for SiteView {
-    fn from(site: Site) -> Self {
-        Self {
-            editable: site.is_editable(),
-            site,
-        }
-    }
-}
-
-impl From<&Site> for SiteView {
-    fn from(site: &Site) -> Self {
-        Self::from(site.clone())
-    }
-}
-
-/// 对外返回的分组节点：带上自己直接挂着的网站与下一级子分组。
-///
-/// 前端侧栏与内容区需要的正是这棵树，所以直接在接口层拼好，
-/// 前端不用再拿两份数组自己组装。
+/// 对外返回的分组节点。
 #[derive(Debug, Serialize)]
 #[serde(rename_all = "camelCase")]
 pub struct NavGroupView {
@@ -133,22 +135,11 @@ pub struct NavGroupView {
 #[derive(Debug, Serialize)]
 #[serde(rename_all = "camelCase")]
 pub struct NavResponse {
-    /// 站点级配置，前端不再自己写死站点名和搜索框提示。
+    /// 站点级配置：前端不再自己写死站点名、搜索提示和提交入口。
     pub site: SiteMeta,
     pub groups: Vec<NavGroupView>,
 }
 
-/// 站点级配置，存在 `data/site.json`，由项目维护者手改。
-#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
-#[serde(rename_all = "camelCase")]
-pub struct SiteMeta {
-    /// 站点名，显示在侧栏顶部与浏览器标题。
-    pub name: String,
-    /// 搜索框占位文案。
-    #[serde(default)]
-    pub search_hint: String,
-}
-
 /// 提交 / 推送一个网站的入参。
 ///
 /// **没有 `categoryId`**：提交方只能给分组名，由后端在「用户创建的分组」里
@@ -156,7 +147,7 @@ pub struct SiteMeta {
 #[derive(Debug, Clone, Deserialize)]
 #[serde(rename_all = "camelCase")]
 pub struct CreateSiteRequest {
-    // 下面三个字段也用 `default`：缺字段时不要让 axum 抛 422 和英文错误，
+    // 这三个也用 `default`：缺字段时不要抛 422 和英文错误，
     // 交给 `validate` 给出统一的中文 400 说明。
     #[serde(default)]
     pub title: String,
@@ -167,7 +158,7 @@ pub struct CreateSiteRequest {
     /// 一级分组名。
     #[serde(default)]
     pub group: String,
-    /// 子分组名，可选；给了就挂到两级下面。
+    /// 子分组名，可选。
     #[serde(default)]
     pub sub_group: String,
     #[serde(default)]
diff --git a/backend/src/store.rs b/backend/src/store.rs
index a4dd1d2..8bb53bd 100644
--- a/backend/src/store.rs
+++ b/backend/src/store.rs
@@ -1,7 +1,7 @@
-//! 数据仓库：启动时把四个 JSON 文件读进内存，之后读内存、写文件。
+//! 数据仓库：`data/nav.json` 读进内存，之后读内存、写文件。
 //!
-//! 「系统内置不可修改」是靠结构保证的：`system-*.json` 只在 `load` 里被读，
-//! 模块里根本没有写这两个文件的函数，任何接口都改不到它们。
+//! 侧栏结构和网站数据在同一份文档里，所以「删掉一个网站」和「它的用户分组要不要
+//! 一起清掉」是同一次写入完成的——不会出现网站没了、侧栏还挂着一个空分组的中间状态。
 
 use std::collections::HashSet;
 use std::fs;
@@ -12,183 +12,69 @@ use serde::de::DeserializeOwned;
 
 use crate::error::{ApiError, StoreError};
 use crate::model::{
-    Category, CreateSiteRequest, NavGroupView, NavResponse, Site, SiteMeta, SiteView, Source,
+    CreateSiteRequest, Group, NavFile, NavGroupView, NavResponse, Site, SiteView, Source,
     UpdateSiteRequest,
 };
 use crate::util::{generate_id, now_iso8601};
-use crate::validate::{self, SiteDraft, SitePatch};
+use crate::validate::{self, SitePatch};
 
 /// 同一分组里每新增一条，排序值加这么多，给以后手工插入留出空隙。
 const ORDER_STEP: i32 = 10;
 
-/// 四个数据文件的位置。
-#[derive(Debug, Clone)]
-pub struct DataPaths {
-    pub site: PathBuf,
-    pub system_categories: PathBuf,
-    pub system_sites: PathBuf,
-    pub user_categories: PathBuf,
-    pub user_sites: PathBuf,
-}
-
-impl DataPaths {
-    pub fn in_dir(dir: &Path) -> Self {
-        Self {
-            site: dir.join("site.json"),
-            system_categories: dir.join("system-categories.json"),
-            system_sites: dir.join("system-sites.json"),
-            user_categories: dir.join("user-categories.json"),
-            user_sites: dir.join("user-sites.json"),
-        }
-    }
-}
+/// 分组层级上限：一级 + 子分组。
+const MAX_GROUP_DEPTH: usize = 2;
 
 /// 内存态数据仓库。
 pub struct Store {
-    paths: DataPaths,
-    site: SiteMeta,
-    system_categories: Vec<Category>,
-    system_sites: Vec<Site>,
-    user_categories: Vec<Category>,
-    user_sites: Vec<Site>,
+    path: PathBuf,
+    file: NavFile,
 }
 
 impl Store {
-    /// 从数据目录读取全部数据。系统文件必须存在；用户文件缺失时当空处理，
-    /// 这样第一次跑起来只需要带上种子数据。
+    /// 从数据目录读取 `nav.json`。
     pub fn load(dir: &Path) -> Result<Self, StoreError> {
-        let paths = DataPaths::in_dir(dir);
-        Ok(Self {
-            site: read_json(&paths.site, true)?,
-            system_categories: read_list(&paths.system_categories, true)?,
-            system_sites: read_list(&paths.system_sites, true)?,
-            user_categories: read_list(&paths.user_categories, false)?,
-            user_sites: read_list(&paths.user_sites, false)?,
-            paths,
-        })
+        let path = dir.join("nav.json");
+        let file: NavFile = read_json(&path)?;
+        Ok(Self { path, file })
     }
 
-    /// 启动自检。不通过就直接让进程退出——数据文件坏了还继续跑，
+    /// 启动自检。不通过就让进程直接退出——数据文件坏了还继续跑，
     /// 只会把更乱的数据写回去。
     pub fn verify(&self) -> Result<(), StoreError> {
-        // 0. 站点配置是必需的：站点名不能空。
-        if self.site.name.trim().is_empty() {
+        if self.file.site.name.trim().is_empty() {
             return Err(StoreError::Integrity(
-                "site.json 里的 name 不能为空".to_string(),
+                "nav.json 里的 site.name 不能为空".to_string(),
             ));
         }
-
-        // 1. source 必须和文件归属一致，防止手改 JSON 越权。
-        for category in &self.system_categories {
-            if !category.source.is_system() {
-                return Err(StoreError::Integrity(format!(
-                    "system-categories.json 里的分组「{}」source 不是 system",
-                    category.id
-                )));
-            }
+        let mut ids = HashSet::new();
+        for group in &self.file.groups {
+            verify_group(group, 1, &mut ids)?;
         }
-        for category in &self.user_categories {
-            if category.source.is_system() {
-                return Err(StoreError::Integrity(format!(
-                    "user-categories.json 里的分组「{}」source 不能是 system",
-                    category.id
-                )));
-            }
-        }
-        for site in &self.system_sites {
-            if !site.source.is_system() {
-                return Err(StoreError::Integrity(format!(
-                    "system-sites.json 里的网站「{}」source 不是 system",
-                    site.id
-                )));
-            }
-        }
-        for site in &self.user_sites {
-            if site.source.is_system() {
-                return Err(StoreError::Integrity(format!(
-                    "user-sites.json 里的网站「{}」source 不能是 system",
-                    site.id
-                )));
-            }
-        }
-
-        // 2. id 不能重复。
-        ensure_unique(self.categories().map(|c| c.id.as_str()), "分组")?;
-        ensure_unique(self.sites().map(|s| s.id.as_str()), "网站")?;
-
-        // 3. 分组层级：parentId 必须存在、必须是一级分组、不能自指。
-        for category in self.categories() {
-            if category.parent_id.is_empty() {
-                continue;
-            }
-            if category.parent_id == category.id {
-                return Err(StoreError::Integrity(format!(
-                    "分组「{}」的 parentId 指向了自己",
-                    category.id
-                )));
-            }
-            let parent = self.find_category(&category.parent_id).ok_or_else(|| {
-                StoreError::Integrity(format!(
-                    "分组「{}」的 parentId「{}」不存在",
-                    category.id, category.parent_id
-                ))
-            })?;
-            if !parent.is_root() {
-                return Err(StoreError::Integrity(format!(
-                    "分组「{}」挂在子分组「{}」下，层级最多两级",
-                    category.id, parent.id
-                )));
-            }
-            if parent.source.is_system() != category.source.is_system() {
-                return Err(StoreError::Integrity(format!(
-                    "分组「{}」和它的父分组「{}」来源不一致",
-                    category.id, parent.id
-                )));
-            }
-        }
-
-        // 4. 每个网站都要挂在一个存在的分组上，而且来源要对得上：
-        //    内置网站只能在内置分组下，提交的网站只能在用户分组下。
-        for site in &self.system_sites {
-            let category = self.require_category(&site.category_id)?;
-            if !category.source.is_system() {
-                return Err(StoreError::Integrity(format!(
-                    "内置网站「{}」挂在了用户分组「{}」下",
-                    site.id, category.id
-                )));
-            }
-        }
-        for site in &self.user_sites {
-            let category = self.require_category(&site.category_id)?;
-            if category.source.is_system() {
-                return Err(StoreError::Integrity(format!(
-                    "提交的网站「{}」挂在了内置分组「{}」下",
-                    site.id, category.id
-                )));
-            }
-        }
-
         Ok(())
     }
 
-    /// 统计信息，给健康检查用。
+    /// 统计信息，给健康检查 / 启动日志用。
     pub fn summary(&self) -> Summary {
-        Summary {
-            sites: self.system_sites.len() + self.user_sites.len(),
-            system_sites: self.system_sites.len(),
-            user_sites: self.user_sites.len(),
-            categories: self.categories().count(),
-        }
+        let mut summary = Summary::default();
+        walk_groups(&self.file.groups, &mut |group| {
+            summary.categories += 1;
+            for site in &group.sites {
+                summary.sites += 1;
+                if site.source.is_system() {
+                    summary.system_sites += 1;
+                } else {
+                    summary.user_sites += 1;
+                }
+            }
+        });
+        summary
     }
 
     /// 侧栏 + 内容区需要的那棵树。
     pub fn nav(&self) -> NavResponse {
-        let mut roots: Vec<&Category> =
-            self.categories().filter(|c| c.is_root()).collect();
-        sort_categories(&mut roots);
         NavResponse {
-            site: self.site.clone(),
-            groups: roots.into_iter().map(|c| self.group_view(c)).collect(),
+            site: self.file.site.clone(),
+            groups: self.file.groups.iter().map(group_view).collect(),
         }
     }
 
@@ -197,157 +83,127 @@ impl Store {
         &mut self,
         request: &CreateSiteRequest,
         source: Source,
-    ) -> Result<Site, ApiError> {
+    ) -> Result<SiteView, ApiError> {
         if source.is_system() {
             return Err(ApiError::internal("新增接口不接受 system 来源"));
         }
         let draft = validate::submission(request)?;
 
-        // 先改副本，落盘成功后再替换内存：写盘失败时不会留下「内存有、磁盘没有」的状态。
-        let mut categories = self.user_categories.clone();
-        let mut sites = self.user_sites.clone();
-
-        let category_id = resolve_user_group(&mut categories, &draft)?;
-        let order = next_order(&sites, &category_id);
+        // 先改副本，落盘成功后再替换内存：写盘失败时不会留下「内存有、磁盘没有」。
+        let mut file = self.file.clone();
+        let category_id = resolve_group_path(&mut file.groups, &draft.group, &draft.sub_group)?;
+        // id 要在拿到分组的可变借用之前算好，否则借用冲突。
+        let id = new_id(site_prefix(source), &collect_ids(&file.groups));
         let now = now_iso8601();
+        let group = find_group_mut(&mut file.groups, &category_id)
+            .ok_or_else(|| ApiError::internal("刚建好的分组找不到了"))?;
         let site = Site {
-            id: new_id(site_prefix(source), &sites),
+            id,
             title: draft.title,
             url: draft.url,
             description: draft.description,
-            category_id,
             source,
-            order,
+            order: next_site_order(group),
             created_at: now.clone(),
             updated_at: now,
             submitted_by: draft.submitted_by,
         };
-        sites.push(site.clone());
+        group.sites.push(site.clone());
 
-        write_list(&self.paths.user_categories, &categories)?;
-        write_list(&self.paths.user_sites, &sites)?;
-        self.user_categories = categories;
-        self.user_sites = sites;
-        Ok(site)
+        write_json(&self.path, &file)?;
+        self.file = file;
+        Ok(SiteView {
+            editable: site.is_editable(),
+            site,
+            category_id,
+        })
     }
 
     /// 修改一个网站。系统内置的直接 403。
-    pub fn update(&mut self, id: &str, request: &UpdateSiteRequest) -> Result<Site, ApiError> {
+    pub fn update(&mut self, id: &str, request: &UpdateSiteRequest) -> Result<SiteView, ApiError> {
         let patch = validate::patch(request)?;
-        let index = self.user_sites.iter().position(|s| s.id == id);
-        let Some(index) = index else {
-            if self.system_sites.iter().any(|s| s.id == id) {
-                return Err(ApiError::forbidden(format!(
-                    "「{id}」是系统内置网站，不能修改"
-                )));
-            }
+        let mut file = self.file.clone();
+
+        let found = find_site(&file.groups, id).map(|(group, site)| (group.id.clone(), site.source));
+        let Some((owner_id, site_source)) = found else {
             return Err(ApiError::not_found(format!("找不到网站：{id}")));
         };
+        if site_source.is_system() {
+            return Err(ApiError::forbidden(format!(
+                "「{id}」是系统内置网站，不能修改"
+            )));
+        }
 
-        let mut categories = self.user_categories.clone();
-        let mut sites = self.user_sites.clone();
-
-        let moved_to = if let Some(group) = &patch.group {
+        // 目标分组：给了 group 就换分组；只给 subGroup 就沿用当前的一级分组。
+        let target_id = if let Some(group) = &patch.group {
             let sub = patch.sub_group.clone().unwrap_or_default();
-            Some(resolve_named_group(&mut categories, group, &sub)?)
+            resolve_group_path(&mut file.groups, group, &sub)?
         } else if let Some(sub) = &patch.sub_group {
             if sub.is_empty() {
-                None
+                owner_id.clone()
             } else {
-                // 只给子分组：沿用条目当前所属的一级分组。
-                let root = root_title_of(&categories, &sites[index].category_id)
+                let root = root_title_of(&file.groups, &owner_id)
                     .ok_or_else(|| ApiError::internal("当前条目的一级分组找不到"))?;
-                Some(resolve_named_group(&mut categories, &root, sub)?)
+                resolve_group_path(&mut file.groups, &root, sub)?
             }
         } else {
-            None
+            owner_id.clone()
         };
 
-        // 排序值要在拿到 `sites[index]` 的可变借用之前算好，否则借用冲突。
-        let moved_order = moved_to.as_ref().map(|id| next_order(&sites, id));
-
-        let site = &mut sites[index];
-        apply_patch(site, patch);
-        if let Some(category_id) = moved_to {
-            if let Some(order) = moved_order {
-                site.order = order;
-            }
-            site.category_id = category_id;
-        }
+        let mut site = take_site(&mut file.groups, id)
+            .ok_or_else(|| ApiError::internal("网站消失在写入过程中"))?;
+        apply_patch(&mut site, patch);
         site.updated_at = now_iso8601();
-        let updated = site.clone();
+        if target_id != owner_id {
+            let target = find_group_mut(&mut file.groups, &target_id)
+                .ok_or_else(|| ApiError::internal("目标分组找不到了"))?;
+            site.order = next_site_order(target);
+        }
 
-        write_list(&self.paths.user_categories, &categories)?;
-        write_list(&self.paths.user_sites, &sites)?;
-        self.user_categories = categories;
-        self.user_sites = sites;
-        Ok(updated)
+        let target = find_group_mut(&mut file.groups, &target_id)
+            .ok_or_else(|| ApiError::internal("目标分组找不到了"))?;
+        target.sites.push(site.clone());
+
+        // 挪走之后原分组可能空了，用户分组跟着清掉。
+        prune_empty_user_groups(&mut file.groups);
+
+        write_json(&self.path, &file)?;
+        self.file = file;
+        Ok(SiteView {
+            editable: site.is_editable(),
+            site,
+            category_id: target_id,
+        })
     }
 
     /// 删除一个网站。系统内置的直接 403。
+    ///
+    /// 删掉之后如果它所在的用户分组空了，这个分组会在同一次写入里一起清掉——
+    /// 侧栏不会留下一个点进去什么都没有的分组。
     pub fn delete(&mut self, id: &str) -> Result<(), ApiError> {
-        if self.system_sites.iter().any(|s| s.id == id) {
+        let mut file = self.file.clone();
+        let found = find_site(&file.groups, id).map(|(_, site)| site.source);
+        let Some(site_source) = found else {
+            return Err(ApiError::not_found(format!("找不到网站：{id}")));
+        };
+        if site_source.is_system() {
             return Err(ApiError::forbidden(format!(
                 "「{id}」是系统内置网站，不能删除"
             )));
         }
-        let mut sites = self.user_sites.clone();
-        let before = sites.len();
-        sites.retain(|s| s.id != id);
-        if sites.len() == before {
-            return Err(ApiError::not_found(format!("找不到网站：{id}")));
-        }
-        write_list(&self.paths.user_sites, &sites)?;
-        self.user_sites = sites;
+
+        take_site(&mut file.groups, id)
+            .ok_or_else(|| ApiError::internal("网站消失在写入过程中"))?;
+        prune_empty_user_groups(&mut file.groups);
+
+        write_json(&self.path, &file)?;
+        self.file = file;
         Ok(())
     }
-
-    // ---- 内部 ----
-
-    fn categories(&self) -> impl Iterator<Item = &Category> {
-        self.system_categories.iter().chain(self.user_categories.iter())
-    }
-
-    fn sites(&self) -> impl Iterator<Item = &Site> {
-        self.system_sites.iter().chain(self.user_sites.iter())
-    }
-
-    fn find_category(&self, id: &str) -> Option<&Category> {
-        self.categories().find(|c| c.id == id)
-    }
-
-    fn require_category(&self, id: &str) -> Result<&Category, StoreError> {
-        self.find_category(id).ok_or_else(|| {
-            StoreError::Integrity(format!("分组「{id}」不存在，但有网站挂在它下面"))
-        })
-    }
-
-    fn group_view(&self, category: &Category) -> NavGroupView {
-        let mut children: Vec<&Category> = self
-            .categories()
-            .filter(|c| c.parent_id == category.id)
-            .collect();
-        sort_categories(&mut children);
-
-        let mut sites: Vec<&Site> = self
-            .sites()
-            .filter(|s| s.category_id == category.id)
-            .collect();
-        sort_sites(&mut sites);
-
-        NavGroupView {
-            id: category.id.clone(),
-            title: category.title.clone(),
-            source: category.source,
-            editable: category.is_editable(),
-            sites: sites.into_iter().map(SiteView::from).collect(),
-            children: children.into_iter().map(|c| self.group_view(c)).collect(),
-        }
-    }
 }
 
 /// 健康检查 / 启动日志用的统计。
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize)]
+#[derive(Debug, Clone, Copy, Default, PartialEq, Eq, Serialize)]
 #[serde(rename_all = "camelCase")]
 pub struct Summary {
     pub sites: usize,
@@ -356,64 +212,174 @@ pub struct Summary {
     pub categories: usize,
 }
 
-/// 解析（必要时新建）用户分组，返回网站该挂到的分组 id。
-///
-/// 只在传进来的 `user_categories` 里查找——内置分组不参与，
-/// 所以提交的内容不可能落进内置分组。
-fn resolve_user_group(
-    categories: &mut Vec<Category>,
-    draft: &SiteDraft,
-) -> Result<String, ApiError> {
-    resolve_named_group(categories, &draft.group, &draft.sub_group)
+// ---- 树操作 ----
+
+/// 遍历所有分组（含子分组）。
+fn walk_groups(groups: &[Group], visit: &mut dyn FnMut(&Group)) {
+    for group in groups {
+        visit(group);
+        walk_groups(&group.children, visit);
+    }
 }
 
-fn resolve_named_group(
-    categories: &mut Vec<Category>,
+/// 收集整棵树里用到的所有 id（分组 + 网站），生成新 id 时用它避重。
+fn collect_ids(groups: &[Group]) -> HashSet<String> {
+    let mut ids = HashSet::new();
+    walk_groups(groups, &mut |group| {
+        ids.insert(group.id.clone());
+        for site in &group.sites {
+            ids.insert(site.id.clone());
+        }
+    });
+    ids
+}
+
+fn find_group_mut<'a>(groups: &'a mut [Group], id: &str) -> Option<&'a mut Group> {
+    for group in groups.iter_mut() {
+        if group.id == id {
+            return Some(group);
+        }
+        if let Some(found) = find_group_mut(&mut group.children, id) {
+            return Some(found);
+        }
+    }
+    None
+}
+
+fn find_site<'a>(groups: &'a [Group], id: &str) -> Option<(&'a Group, &'a Site)> {
+    for group in groups {
+        if let Some(site) = group.sites.iter().find(|site| site.id == id) {
+            return Some((group, site));
+        }
+        if let Some(found) = find_site(&group.children, id) {
+            return Some(found);
+        }
+    }
+    None
+}
+
+/// 把网站从树里取出来。
+fn take_site(groups: &mut [Group], id: &str) -> Option<Site> {
+    for group in groups.iter_mut() {
+        if let Some(index) = group.sites.iter().position(|site| site.id == id) {
+            return Some(group.sites.remove(index));
+        }
+        if let Some(site) = take_site(&mut group.children, id) {
+            return Some(site);
+        }
+    }
+    None
+}
+
+/// 找出某个分组所属的一级分组标题。
+fn root_title_of(groups: &[Group], id: &str) -> Option<String> {
+    for root in groups {
+        if root.id == id || root.children.iter().any(|child| child.id == id) {
+            return Some(root.title.clone());
+        }
+    }
+    None
+}
+
+fn next_site_order(group: &Group) -> i32 {
+    group.sites.iter().map(|site| site.order).max().unwrap_or(0) + ORDER_STEP
+}
+
+/// 解析（必要时新建）用户分组，返回网站该挂到的分组 id。
+///
+/// 只在 `source != system` 的组里查找——内置分组不参与，
+/// 所以提交的内容不可能落进内置分组。
+fn resolve_group_path(
+    groups: &mut Vec<Group>,
     group: &str,
     sub_group: &str,
 ) -> Result<String, ApiError> {
-    let root_id = match categories.iter().find(|c| c.is_root() && c.title == group) {
-        Some(found) => found.id.clone(),
-        None => push_category(categories, group, "")?,
+    let root_id = match groups
+        .iter()
+        .position(|item| !item.source.is_system() && item.title == group)
+    {
+        Some(index) => groups[index].id.clone(),
+        None => push_root_group(groups, group)?,
     };
     if sub_group.is_empty() {
         return Ok(root_id);
     }
-    match categories
+
+    let existing_child = groups
         .iter()
-        .find(|c| c.parent_id == root_id && c.title == sub_group)
-    {
-        Some(found) => Ok(found.id.clone()),
-        None => push_category(categories, sub_group, &root_id),
+        .find(|item| item.id == root_id)
+        .and_then(|root| {
+            root.children
+                .iter()
+                .find(|child| !child.source.is_system() && child.title == sub_group)
+        })
+        .map(|child| child.id.clone());
+    if let Some(id) = existing_child {
+        return Ok(id);
     }
+    push_child_group(groups, &root_id, sub_group)
 }
 
-fn push_category(
-    categories: &mut Vec<Category>,
-    title: &str,
-    parent_id: &str,
-) -> Result<String, ApiError> {
-    let id = new_id("g", categories);
-    let order = categories
-        .iter()
-        .filter(|c| c.parent_id == parent_id)
-        .map(|c| c.order)
-        .max()
-        .unwrap_or(0)
-        + ORDER_STEP;
+fn push_root_group(groups: &mut Vec<Group>, title: &str) -> Result<String, ApiError> {
+    let id = new_id("g", &collect_ids(groups));
+    let order = groups.iter().map(|group| group.order).max().unwrap_or(0) + ORDER_STEP;
     let now = now_iso8601();
-    categories.push(Category {
+    groups.push(Group {
         id: id.clone(),
         title: title.to_string(),
-        parent_id: parent_id.to_string(),
         source: Source::Submission,
         order,
         created_at: now.clone(),
         updated_at: now,
+        sites: Vec::new(),
+        children: Vec::new(),
     });
     Ok(id)
 }
 
+fn push_child_group(
+    groups: &mut [Group],
+    parent_id: &str,
+    title: &str,
+) -> Result<String, ApiError> {
+    let id = new_id("g", &collect_ids(groups));
+    let now = now_iso8601();
+    let parent = groups
+        .iter_mut()
+        .find(|group| group.id == parent_id)
+        .ok_or_else(|| ApiError::internal("父分组找不到了"))?;
+    let order = parent
+        .children
+        .iter()
+        .map(|child| child.order)
+        .max()
+        .unwrap_or(0)
+        + ORDER_STEP;
+    parent.children.push(Group {
+        id: id.clone(),
+        title: title.to_string(),
+        source: Source::Submission,
+        order,
+        created_at: now.clone(),
+        updated_at: now,
+        sites: Vec::new(),
+        children: Vec::new(),
+    });
+    Ok(id)
+}
+
+/// 递归清掉「空掉了的用户分组」：没有网站、也没有子分组的用户分组不再保留。
+///
+/// 内置分组永远不动——那是项目维护者手写的结构。
+fn prune_empty_user_groups(groups: &mut Vec<Group>) {
+    for group in groups.iter_mut() {
+        prune_empty_user_groups(&mut group.children);
+    }
+    groups.retain(|group| {
+        group.source.is_system() || !group.sites.is_empty() || !group.children.is_empty()
+    });
+}
+
 fn apply_patch(site: &mut Site, patch: SitePatch) {
     if let Some(value) = patch.title {
         site.title = value;
@@ -426,28 +392,6 @@ fn apply_patch(site: &mut Site, patch: SitePatch) {
     }
 }
 
-/// 找出某个分组所属的一级分组标题。
-fn root_title_of(categories: &[Category], category_id: &str) -> Option<String> {
-    let category = categories.iter().find(|c| c.id == category_id)?;
-    if category.is_root() {
-        return Some(category.title.clone());
-    }
-    categories
-        .iter()
-        .find(|c| c.id == category.parent_id)
-        .map(|root| root.title.clone())
-}
-
-fn next_order(sites: &[Site], category_id: &str) -> i32 {
-    sites
-        .iter()
-        .filter(|s| s.category_id == category_id)
-        .map(|s| s.order)
-        .max()
-        .unwrap_or(0)
-        + ORDER_STEP
-}
-
 fn site_prefix(source: Source) -> &'static str {
     match source {
         Source::Submission => "s",
@@ -457,11 +401,10 @@ fn site_prefix(source: Source) -> &'static str {
     }
 }
 
-/// 生成一个当前集合里没用过的 id。
-fn new_id<T: HasId>(prefix: &str, existing: &[T]) -> String {
+fn new_id(prefix: &str, used: &HashSet<String>) -> String {
     for _ in 0..8 {
         let candidate = generate_id(prefix);
-        if !existing.iter().any(|item| item.id() == candidate) {
+        if !used.contains(&candidate) {
             return candidate;
         }
     }
@@ -469,71 +412,87 @@ fn new_id<T: HasId>(prefix: &str, existing: &[T]) -> String {
     format!("{prefix}-{}", now_iso8601().replace([':', '-'], ""))
 }
 
-trait HasId {
-    fn id(&self) -> &str;
-}
-
-impl HasId for Site {
-    fn id(&self) -> &str {
-        &self.id
-    }
-}
-
-impl HasId for Category {
-    fn id(&self) -> &str {
-        &self.id
-    }
-}
-
-fn sort_categories(items: &mut [&Category]) {
-    items.sort_by(|a, b| {
+fn group_view(group: &Group) -> NavGroupView {
+    let mut children: Vec<&Group> = group.children.iter().collect();
+    children.sort_by(|a, b| {
         a.order
             .cmp(&b.order)
             .then_with(|| a.created_at.cmp(&b.created_at))
             .then_with(|| a.id.cmp(&b.id))
     });
-}
-
-fn sort_sites(items: &mut [&Site]) {
-    items.sort_by(|a, b| {
+    let mut sites: Vec<&Site> = group.sites.iter().collect();
+    sites.sort_by(|a, b| {
         a.order
             .cmp(&b.order)
             .then_with(|| a.created_at.cmp(&b.created_at))
             .then_with(|| a.id.cmp(&b.id))
     });
+
+    NavGroupView {
+        id: group.id.clone(),
+        title: group.title.clone(),
+        source: group.source,
+        editable: group.is_editable(),
+        sites: sites
+            .into_iter()
+            .map(|site| SiteView {
+                site: site.clone(),
+                category_id: group.id.clone(),
+                editable: site.is_editable(),
+            })
+            .collect(),
+        children: children.into_iter().map(group_view).collect(),
+    }
 }
 
-fn ensure_unique<'a>(ids: impl Iterator<Item = &'a str>, label: &str) -> Result<(), StoreError> {
-    let mut seen = HashSet::new();
-    for id in ids {
-        if !seen.insert(id) {
-            return Err(StoreError::Integrity(format!("{label} id 重复：{id}")));
+/// 分组层级、id 唯一性、以及「内置分组下只能放内置网站」这几条自检。
+fn verify_group(
+    group: &Group,
+    depth: usize,
+    ids: &mut HashSet<String>,
+) -> Result<(), StoreError> {
+    if depth > MAX_GROUP_DEPTH {
+        return Err(StoreError::Integrity(format!(
+            "分组「{}」在第 {depth} 层，最多只能两级",
+            group.id
+        )));
+    }
+    if group.title.trim().is_empty() {
+        return Err(StoreError::Integrity(format!(
+            "分组「{}」的标题不能为空",
+            group.id
+        )));
+    }
+    if !ids.insert(group.id.clone()) {
+        return Err(StoreError::Integrity(format!(
+            "分组 id 重复：{}",
+            group.id
+        )));
+    }
+    for site in &group.sites {
+        if !ids.insert(site.id.clone()) {
+            return Err(StoreError::Integrity(format!(
+                "网站 id 重复：{}",
+                site.id
+            )));
         }
+        if group.source.is_system() != site.source.is_system() {
+            return Err(StoreError::Integrity(format!(
+                "分组「{}」和它下面的网站「{}」来源不一致：内置分组只能放内置网站，\
+                 提交的网站只能放在用户分组下",
+                group.id, site.id
+            )));
+        }
+    }
+    for child in &group.children {
+        verify_group(child, depth + 1, ids)?;
     }
     Ok(())
 }
 
-/// 读一个 JSON 数组。`required` 为 false 时，文件不存在按空数组处理。
-fn read_list<T: DeserializeOwned>(path: &Path, required: bool) -> Result<Vec<T>, StoreError> {
+fn read_json<T: DeserializeOwned>(path: &Path) -> Result<T, StoreError> {
     if !path.exists() {
-        if required {
-            return Err(StoreError::Io(format!("找不到数据文件：{}", path.display())));
-        }
-        return Ok(Vec::new());
-    }
-    let text = fs::read_to_string(path)
-        .map_err(|e| StoreError::Io(format!("{}：{e}", path.display())))?;
-    serde_json::from_str(&text)
-        .map_err(|e| StoreError::Json(format!("{}：{e}", path.display())))
-}
-
-/// 读一个 JSON 对象。`required` 为 false 时，文件不存在会报错并要求补上——
-/// 站点配置是必需项，缺了就说明数据目录不完整。
-fn read_json<T: DeserializeOwned>(path: &Path, required: bool) -> Result<T, StoreError> {
-    if !path.exists() {
-        if required {
-            return Err(StoreError::Io(format!("找不到数据文件：{}", path.display())));
-        }
+        return Err(StoreError::Io(format!("找不到数据文件：{}", path.display())));
     }
     let text = fs::read_to_string(path)
         .map_err(|e| StoreError::Io(format!("{}：{e}", path.display())))?;
@@ -542,13 +501,13 @@ fn read_json<T: DeserializeOwned>(path: &Path, required: bool) -> Result<T, Stor
 }
 
 /// 原子写：先写临时文件再改名，避免写到一半断电把数据文件写坏。
-fn write_list<T: Serialize>(path: &Path, value: &[T]) -> Result<(), StoreError> {
+fn write_json(path: &Path, value: &NavFile) -> Result<(), StoreError> {
     if let Some(parent) = path.parent() {
         fs::create_dir_all(parent)
             .map_err(|e| StoreError::Io(format!("{}：{e}", parent.display())))?;
     }
-    let mut text = serde_json::to_string_pretty(value)
-        .map_err(|e| StoreError::Json(e.to_string()))?;
+    let mut text =
+        serde_json::to_string_pretty(value).map_err(|e| StoreError::Json(e.to_string()))?;
     text.push('\n');
     let tmp = path.with_extension("json.tmp");
     fs::write(&tmp, text).map_err(|e| StoreError::Io(format!("{}：{e}", tmp.display())))?;
@@ -557,38 +516,47 @@ fn write_list<T: Serialize>(path: &Path, value: &[T]) -> Result<(), StoreError>
 }
 
 #[cfg(test)]
-/// 造一份最小的种子数据，供单元测试与接口测试共用。
+/// 造一份最小的 `nav.json`，供单元测试与接口测试共用。
 pub fn seed_for_test(dir: &Path) {
     fs::write(
-        dir.join("site.json"),
-        r#"{ "name": "Suxing Nav", "searchHint": "输入关键字搜索全网资源..." }"#,
-    )
-    .expect("写测试数据失败");
-    fs::write(
-        dir.join("system-categories.json"),
-        r#"[
-  { "id": "common", "title": "常用推荐", "parentId": "", "source": "system", "order": 10,
-    "createdAt": "2026-09-13T10:29:48Z", "updatedAt": "2026-09-13T10:29:48Z" },
-  { "id": "materials", "title": "素材资源", "parentId": "", "source": "system", "order": 20,
-    "createdAt": "2026-09-13T10:29:48Z", "updatedAt": "2026-09-13T10:29:48Z" },
-  { "id": "design", "title": "UI 设计", "parentId": "materials", "source": "system", "order": 10,
-    "createdAt": "2026-09-13T10:29:48Z", "updatedAt": "2026-09-13T10:29:48Z" }
-]"#,
-    )
-    .expect("写测试数据失败");
-    fs::write(
-        dir.join("system-sites.json"),
-        r#"[
-  { "id": "github", "title": "GitHub", "url": "https://github.com", "description": "代码托管与开源社区",
-    "categoryId": "common", "source": "system", "order": 10,
-    "createdAt": "2026-09-13T10:29:48Z", "updatedAt": "2026-09-13T10:29:48Z", "submittedBy": "" },
-  { "id": "zhihu", "title": "知乎", "url": "https://www.zhihu.com", "description": "深度内容问答社区",
-    "categoryId": "common", "source": "system", "order": 20,
-    "createdAt": "2026-09-13T10:29:48Z", "updatedAt": "2026-09-13T10:29:48Z", "submittedBy": "" },
-  { "id": "figma", "title": "Figma", "url": "https://www.figma.com", "description": "协同界面设计工具",
-    "categoryId": "design", "source": "system", "order": 10,
-    "createdAt": "2026-09-13T10:29:48Z", "updatedAt": "2026-09-13T10:29:48Z", "submittedBy": "" }
-]"#,
+        dir.join("nav.json"),
+        r#"{
+  "site": { "name": "Suxing Nav", "searchHint": "输入关键字搜索全网资源...", "submitUrl": "https://mattermost.example.com" },
+  "groups": [
+    {
+      "id": "common", "title": "常用推荐", "source": "system", "order": 10,
+      "createdAt": "2026-09-13T10:29:48Z", "updatedAt": "2026-09-13T10:29:48Z",
+      "sites": [
+        { "id": "github", "title": "GitHub", "url": "https://github.com",
+          "description": "代码托管与开源社区", "source": "system", "order": 10,
+          "createdAt": "2026-09-13T10:29:48Z", "updatedAt": "2026-09-13T10:29:48Z",
+          "submittedBy": "" },
+        { "id": "zhihu", "title": "知乎", "url": "https://www.zhihu.com",
+          "description": "深度内容问答社区", "source": "system", "order": 20,
+          "createdAt": "2026-09-13T10:29:48Z", "updatedAt": "2026-09-13T10:29:48Z",
+          "submittedBy": "" }
+      ],
+      "children": []
+    },
+    {
+      "id": "materials", "title": "素材资源", "source": "system", "order": 20,
+      "createdAt": "2026-09-13T10:29:48Z", "updatedAt": "2026-09-13T10:29:48Z",
+      "sites": [],
+      "children": [
+        { "id": "design", "title": "UI 设计", "source": "system", "order": 10,
+          "createdAt": "2026-09-13T10:29:48Z", "updatedAt": "2026-09-13T10:29:48Z",
+          "sites": [
+            { "id": "figma", "title": "Figma", "url": "https://www.figma.com",
+              "description": "协同界面设计工具", "source": "system", "order": 10,
+              "createdAt": "2026-09-13T10:29:48Z", "updatedAt": "2026-09-13T10:29:48Z",
+              "submittedBy": "" }
+          ],
+          "children": []
+        }
+      ]
+    }
+  ]
+}"#,
     )
     .expect("写测试数据失败");
 }
@@ -598,10 +566,6 @@ mod tests {
     use super::*;
     use tempfile::TempDir;
 
-    fn write(path: &Path, text: &str) {
-        fs::write(path, text).expect("写测试数据失败");
-    }
-
     fn store_in(temp: &TempDir) -> Store {
         seed_for_test(temp.path());
         let store = Store::load(temp.path()).expect("加载失败");
@@ -621,19 +585,26 @@ mod tests {
     }
 
     #[test]
-    fn loads_seed_data_and_builds_nav_tree() {
+    fn loads_one_file_and_builds_nav_tree() {
         let temp = TempDir::new().unwrap();
         let store = store_in(&temp);
 
         let nav = store.nav();
+        assert_eq!(nav.site.name, "Suxing Nav");
         assert_eq!(nav.groups.len(), 2, "两个一级分组");
         assert_eq!(nav.groups[0].id, "common");
-        assert_eq!(nav.groups[0].sites.len(), 2, "common 下有两条");
-        assert_eq!(nav.groups[1].id, "materials");
-        assert_eq!(nav.groups[1].children.len(), 1);
+        assert_eq!(nav.groups[0].sites.len(), 2);
+        assert_eq!(nav.groups[0].sites[0].site.id, "github");
+        // categoryId 由位置推导出来，仍然输出给前端。
+        assert_eq!(nav.groups[0].sites[0].category_id, "common");
+        assert!(!nav.groups[0].sites[0].editable);
         assert_eq!(nav.groups[1].children[0].id, "design");
-        assert_eq!(nav.groups[1].children[0].sites[0].site.id, "figma");
-        assert!(!nav.groups[1].children[0].sites[0].editable, "内置条目不可编辑");
+        assert_eq!(nav.groups[1].children[0].sites[0].category_id, "design");
+
+        let summary = store.summary();
+        assert_eq!(summary.sites, 3);
+        assert_eq!(summary.system_sites, 3);
+        assert_eq!(summary.categories, 3);
     }
 
     #[test]
@@ -642,22 +613,27 @@ mod tests {
         let mut store = store_in(&temp);
 
         let site = store
-            .create(&submission("Hugging Face", "https://huggingface.co", "AI 工具", "模型社区"), Source::Submission)
+            .create(
+                &submission("Hugging Face", "https://huggingface.co", "AI 工具", "模型社区"),
+                Source::Submission,
+            )
             .expect("提交应当成功");
+        assert!(site.site.id.starts_with("s-"));
+        assert_eq!(site.site.source, Source::Submission);
 
-        assert!(site.id.starts_with("s-"), "用户提交的 id 用 s- 前缀：{}", site.id);
-        assert!(site.category_id.starts_with("g-"), "分组是新建的：{}", site.category_id);
-        assert_eq!(site.source, Source::Submission);
-        assert!(site.is_editable());
-
-        // 新分组挂在第一位，且是两级结构。
         let nav = store.nav();
-        let created_root = nav.groups.iter().find(|g| g.id != "common" && g.id != "materials").unwrap();
-        assert_eq!(created_root.title, "AI 工具");
-        assert_eq!(created_root.children[0].title, "模型社区");
-        assert_eq!(created_root.children[0].sites[0].site.id, site.id);
+        let root = nav
+            .groups
+            .iter()
+            .find(|group| group.title == "AI 工具")
+            .expect("新分组应当存在");
+        assert!(root.editable);
+        let child = &root.children[0];
+        assert_eq!(child.title, "模型社区");
+        assert_eq!(child.sites[0].site.id, site.site.id);
+        assert_eq!(child.sites[0].category_id, child.id);
 
-        // 真的写到磁盘了：重新加载还能看到。
+        // 重新加载：数据真的落盘了。
         let reloaded = Store::load(temp.path()).expect("重新加载失败");
         reloaded.verify().expect("重新加载后自检失败");
         assert_eq!(reloaded.summary().user_sites, 1);
@@ -667,16 +643,22 @@ mod tests {
     fn same_group_name_is_reused() {
         let temp = TempDir::new().unwrap();
         let mut store = store_in(&temp);
-
-        let first = store
+        store
             .create(&submission("A", "https://a.com", "AI 工具", "模型社区"), Source::Submission)
             .unwrap();
-        let second = store
+        store
             .create(&submission("B", "https://b.com", "AI 工具", "模型社区"), Source::Submission)
             .unwrap();
 
-        assert_eq!(first.category_id, second.category_id, "同名分组应当复用");
-        assert_eq!(store.summary().categories, 5, "只多了一级 + 子分组两个");
+        let nav = store.nav();
+        let created: Vec<&NavGroupView> = nav
+            .groups
+            .iter()
+            .filter(|group| group.title == "AI 工具")
+            .collect();
+        assert_eq!(created.len(), 1, "同名分组只应有一个");
+        assert_eq!(created[0].children.len(), 1);
+        assert_eq!(created[0].children[0].sites.len(), 2);
     }
 
     #[test]
@@ -685,19 +667,30 @@ mod tests {
         let mut store = store_in(&temp);
 
         // 故意用内置分组的名字提交。
-        let site = store
-            .create(&submission("Fake", "https://fake.com", "素材资源", "UI 设计"), Source::Submission)
-            .unwrap();
+        store
+            .create(
+                &submission("Fake", "https://fake.com", "素材资源", "UI 设计"),
+                Source::Submission,
+            )
+            .expect("提交应当成功");
 
-        assert_ne!(site.category_id, "design", "不能挂进内置子分组");
-        assert!(site.category_id.starts_with("g-"), "应当在用户分组里");
-
-        // 内置分组下的内容没被动过。
         let nav = store.nav();
-        let materials = nav.groups.iter().find(|g| g.id == "materials").unwrap();
-        assert_eq!(materials.children[0].id, "design");
-        assert_eq!(materials.children[0].sites.len(), 1, "design 下仍然只有 Figma");
-        assert!(materials.children[0].sites[0].site.id == "figma");
+        let builtin = nav
+            .groups
+            .iter()
+            .find(|group| group.id == "materials")
+            .unwrap();
+        assert_eq!(builtin.children[0].id, "design");
+        assert_eq!(builtin.children[0].sites.len(), 1, "内置子分组没被动过");
+        assert!(!builtin.children[0].sites[0].editable);
+
+        // 用户分组里多了一个同名的新分组。
+        let user_root = nav
+            .groups
+            .iter()
+            .find(|group| group.editable && group.title == "素材资源")
+            .expect("应当新建用户分组，而不是复用内置的");
+        assert_eq!(user_root.children[0].sites.len(), 1);
     }
 
     #[test]
@@ -711,9 +704,10 @@ mod tests {
         };
         let err = store.update("github", &update).unwrap_err();
         assert_eq!(err.status(), axum::http::StatusCode::FORBIDDEN);
-
-        let err = store.delete("github").unwrap_err();
-        assert_eq!(err.status(), axum::http::StatusCode::FORBIDDEN);
+        assert_eq!(
+            store.delete("github").unwrap_err().status(),
+            axum::http::StatusCode::FORBIDDEN
+        );
     }
 
     #[test]
@@ -729,16 +723,44 @@ mod tests {
             url: Some("https://a2.com".to_string()),
             ..Default::default()
         };
-        let updated = store.update(&site.id, &update).unwrap();
-        assert_eq!(updated.title, "新名字");
-        assert_eq!(updated.url, "https://a2.com");
-        assert_eq!(updated.category_id, site.category_id, "没传 group 就不换分组");
+        let updated = store.update(&site.site.id, &update).unwrap();
+        assert_eq!(updated.site.title, "新名字");
+        assert_eq!(updated.site.url, "https://a2.com");
 
-        store.delete(&site.id).unwrap();
+        store.delete(&site.site.id).unwrap();
         assert_eq!(store.summary().user_sites, 0);
+        assert_eq!(
+            store.delete(&site.site.id).unwrap_err().status(),
+            axum::http::StatusCode::NOT_FOUND
+        );
+    }
 
-        let err = store.delete(&site.id).unwrap_err();
-        assert_eq!(err.status(), axum::http::StatusCode::NOT_FOUND);
+    #[test]
+    fn deleting_the_last_site_removes_the_empty_user_group() {
+        let temp = TempDir::new().unwrap();
+        let mut store = store_in(&temp);
+        let first = store
+            .create(&submission("A", "https://a.com", "AI 工具", "模型社区"), Source::Submission)
+            .unwrap();
+        let second = store
+            .create(&submission("B", "https://b.com", "AI 工具", "模型社区"), Source::Submission)
+            .unwrap();
+
+        // 删掉第一条：分组还在（还有一条）。
+        store.delete(&first.site.id).unwrap();
+        let nav = store.nav();
+        assert!(nav.groups.iter().any(|group| group.title == "AI 工具"));
+
+        // 删掉最后一条：一级分组和子分组一起消失，侧栏不会留下空壳。
+        store.delete(&second.site.id).unwrap();
+        let nav = store.nav();
+        assert!(
+            !nav.groups.iter().any(|group| group.title == "AI 工具"),
+            "空掉的用户分组应当一起清掉"
+        );
+        assert_eq!(store.summary().categories, 3, "只剩内置的三个分组");
+        // 内置分组一条没动。
+        assert_eq!(store.summary().system_sites, 3);
     }
 
     #[test]
@@ -754,75 +776,66 @@ mod tests {
             sub_group: Some("笔记".to_string()),
             ..Default::default()
         };
-        let updated = store.update(&site.id, &update).unwrap();
-        assert_ne!(updated.category_id, site.category_id);
+        let updated = store.update(&site.site.id, &update).unwrap();
 
         let nav = store.nav();
+        // 旧分组空了，被清掉。
+        assert!(!nav.groups.iter().any(|group| group.title == "AI 工具"));
         let moved = nav
             .groups
             .iter()
-            .find(|g| g.title == "效率工具")
+            .find(|group| group.title == "效率工具")
             .expect("新分组应当存在");
         assert_eq!(moved.children[0].title, "笔记");
-        assert_eq!(moved.children[0].sites[0].site.id, site.id);
+        assert_eq!(moved.children[0].sites[0].site.id, updated.site.id);
     }
 
     #[test]
-    fn verify_rejects_a_tampered_file() {
+    fn verify_rejects_a_tampered_source() {
         let temp = TempDir::new().unwrap();
         seed_for_test(temp.path());
-        // 把内置网站标成 api 来源，模拟手改 JSON 越权。
-        write(
-            &temp.path().join("system-sites.json"),
-            r#"[{ "id": "github", "title": "GitHub", "url": "https://github.com",
-                 "categoryId": "common", "source": "api",
-                 "createdAt": "2026-09-13T10:29:48Z", "updatedAt": "2026-09-13T10:29:48Z" }]"#,
-        );
-        let store = Store::load(temp.path()).expect("加载应当成功");
-        let err = store.verify().unwrap_err();
-        assert!(err.to_string().contains("source"), "{err}");
-    }
+        // 把内置分组里的网站标成 api，模拟手改 JSON 越权。
+        let path = temp.path().join("nav.json");
+        let text = fs::read_to_string(&path)
+            .unwrap()
+            .replace(
+                r#""description": "代码托管与开源社区", "source": "system""#,
+                r#""description": "代码托管与开源社区", "source": "api""#,
+            );
+        fs::write(&path, text).unwrap();
 
-    #[test]
-    fn verify_rejects_user_site_under_system_group() {
-        let temp = TempDir::new().unwrap();
-        seed_for_test(temp.path());
-        write(
-            &temp.path().join("user-sites.json"),
-            r#"[{ "id": "s-1", "title": "A", "url": "https://a.com",
-                 "categoryId": "common", "source": "submission",
-                 "createdAt": "2026-09-13T10:29:48Z", "updatedAt": "2026-09-13T10:29:48Z" }]"#,
-        );
         let store = Store::load(temp.path()).expect("加载应当成功");
         let err = store.verify().unwrap_err();
-        assert!(err.to_string().contains("内置分组"), "{err}");
+        assert!(err.to_string().contains("来源不一致"), "{err}");
     }
 
     #[test]
     fn verify_rejects_three_level_groups() {
         let temp = TempDir::new().unwrap();
-        seed_for_test(temp.path());
-        write(
-            &temp.path().join("system-categories.json"),
-            r#"[{ "id": "materials", "title": "素材资源", "parentId": "", "source": "system", "order": 10,
-                 "createdAt": "2026-09-13T10:29:48Z", "updatedAt": "2026-09-13T10:29:48Z" },
-                { "id": "design", "title": "UI 设计", "parentId": "materials", "source": "system", "order": 10,
-                 "createdAt": "2026-09-13T10:29:48Z", "updatedAt": "2026-09-13T10:29:48Z" },
-                { "id": "deep", "title": "更深一层", "parentId": "design", "source": "system", "order": 10,
-                 "createdAt": "2026-09-13T10:29:48Z", "updatedAt": "2026-09-13T10:29:48Z" }]"#,
-        );
-        write(&temp.path().join("system-sites.json"), "[]");
+        fs::write(
+            temp.path().join("nav.json"),
+            r#"{
+  "site": { "name": "N", "searchHint": "", "submitUrl": "" },
+  "groups": [
+    { "id": "a", "title": "A", "source": "system", "order": 10,
+      "createdAt": "2026-09-13T10:29:48Z", "updatedAt": "2026-09-13T10:29:48Z",
+      "sites": [],
+      "children": [
+        { "id": "b", "title": "B", "source": "system", "order": 10,
+          "createdAt": "2026-09-13T10:29:48Z", "updatedAt": "2026-09-13T10:29:48Z",
+          "sites": [],
+          "children": [
+            { "id": "c", "title": "C", "source": "system", "order": 10,
+              "createdAt": "2026-09-13T10:29:48Z", "updatedAt": "2026-09-13T10:29:48Z",
+              "sites": [], "children": [] }
+          ] }
+      ] }
+  ]
+}"#,
+        )
+        .unwrap();
         let store = Store::load(temp.path()).expect("加载应当成功");
         let err = store.verify().unwrap_err();
         assert!(err.to_string().contains("两级"), "{err}");
     }
-
-    #[test]
-    fn missing_user_files_are_treated_as_empty() {
-        let temp = TempDir::new().unwrap();
-        seed_for_test(temp.path());
-        let store = Store::load(temp.path()).expect("加载失败");
-        store.verify().expect("自检失败");
-        assert_eq!(store.summary().user_sites, 0);
-    }
 }
diff --git a/docs/backend-site-schema.md b/docs/backend-site-schema.md
index a33ce87..d4e1b60 100644
--- a/docs/backend-site-schema.md
+++ b/docs/backend-site-schema.md
@@ -1,7 +1,7 @@
 # 后端数据结构设计：网站与分组
 
-> 本文是设计稿，已按此实现。代码在 `backend/`，接口与运行方式见
-> [backend/README.md](../backend/README.md)。
+> 本文是设计稿。实现时按「侧栏结构和网站绑定到一个文件、删除时同步清理」调整过，
+> 现状见 [backend/README.md](../backend/README.md)。
 
 ## 1. 需求与边界
 
@@ -158,17 +158,14 @@ pub enum SiteSource {
 
 ```
 backend/data/
-├── site.json                # 站点名与搜索框提示，只读
-├── system-categories.json   # 内置分组，只读，项目维护者手写
-├── system-sites.json        # 内置网站，只读
-├── user-categories.json     # 提交时创建的分组，可写
-└── user-sites.json          # 提交 / 推送的网站，可写
+└── nav.json                 # 站点信息 + 分组结构（含网站），一份文档
 ```
 
-- 读：启动时全量加载进内存，之后都从内存读，不再碰磁盘。
-- 写：只写 `user-*.json` 两个文件。**代码里不存在写 `system-*.json` 的路径**，
-  「不可修改」靠结构保证，而不是靠每处调用都记得判断。
-- 写盘用「先写临时文件再改名」，避免写到一半断电把文件写坏。
+- 读：启动时加载进内存，之后都从内存读，不再碰磁盘。
+- 写：整份文档一起写回，但改的只会是 `source != system` 的那部分。
+- 网站直接挂在分组的 `sites` 里，不再自己记 `categoryId`——
+  归属由位置表达，删掉分组不会留下指向空处的引用。
+- 删除网站时，如果它所在的用户分组空了，会在**同一次写入**里一起清掉。
 - JSON 用 2 空格缩进、保留中文原文，方便直接看 diff。
 
 ### 5.1 启动时的自检
diff --git a/docs/frontend-architecture.md b/docs/frontend-architecture.md
index d2b696e..c795c68 100644
--- a/docs/frontend-architecture.md
+++ b/docs/frontend-architecture.md
@@ -104,11 +104,7 @@ lib/
                 ├── link_search_field.dart          # 搜索框（含聚焦光晕）
                 ├── link_section_view.dart          # 分区标题 + 自适应网格
                 ├── link_card.dart                  # 站点卡片
-                ├── back_to_top_button.dart         # 右下角圆形回到顶部
-                ├── dialog_buttons.dart             # 对话框的主/次按钮
-                ├── confirm_dialog.dart             # 通用确认框（删除前确认）
-                ├── site_form_dialog.dart           # 网站表单（新增 / 编辑共用）
-                └── ...
+                └── back_to_top_button.dart         # 右下角圆形回到顶部
 ```
 
 `test/` 展开（与 `lib/` 一一对应）：
@@ -143,15 +139,15 @@ main.dart → app.dart
 数据流：
 
 ```
-后端 GET /api/nav ──▶ { site: { name, searchHint }, groups: [ { …, sites: [] } ] }
+后端 GET /api/nav ──▶ { site: { name, searchHint, submitUrl }, groups: [ … ] }
    │                                        ▲
    │                                        │ POST /api/sites（提交）
    │                                        │ PATCH /api/sites/{id}（编辑）
    │                                        │ DELETE /api/sites/{id}（删除）
-   ▼                                        │
+   ▼                                        │   ← 这三个接口页面上暂时不用
 HttpHomeRepository ──实现──▶ HomeRepository（读 / 提交 / 编辑 / 删除）
    │  把分组树映射成前端模型：分组 → 侧栏导航；有网站的组 → 内容分区；
-   │  每个网站带 editable，决定卡片上有没有编辑/删除入口
+   │  每个网站带 editable（页面暂时不据此渲染任何入口）
    ▼
 HomePage State：_load() 拿到 HomeData，并在加载中 / 失败（可重试）/ 完成三种状态间切换
    │  （页面持有交互状态：当前分区、侧栏折叠、已展开的分组）
@@ -383,7 +379,7 @@ CSS 的 `max-height: 0` 只是视觉上收起了子菜单，DOM 里那些链接
 | 检查 | 命令 | 结果 |
 | --- | --- | --- |
 | 静态分析 | `flutter analyze` | 1 条告警（`sidebar_nav.dart` 里 `_NavRow` 的 `super.key` 从未被传入，见下方说明） |
-| 单元与组件测试 | `flutter test` | 57 个用例通过，6 个失败（都是侧栏实现与既有用例不一致，见下方说明） |
+| 单元与组件测试 | `flutter test` | 47 个用例通过，6 个失败（都是侧栏实现与既有用例不一致，见下方说明） |
 | Web 构建 | `flutter build web --no-wasm-dry-run` | 构建成功 |
 
 > 上面这两处不是本轮对接引入的：`e2cc3ac` 那次提交重写了侧栏（行内改用 `Container`、
@@ -401,18 +397,12 @@ CSS 的 `max-height: 0` 只是视觉上收起了子菜单，DOM 里那些链接
 - 导航：高亮固定写在第一个条目上；点有对应分区的导航会滚过去且高亮不变；点 `#icon` 这类没有对应元素的导航滚动偏移不变。
 - 搜索框：输入后仍是两个分区、五张卡片（不过滤）。
 - 滚动：滚动主内容不会重建侧栏、也不会改动高亮；回到顶部把偏移归零。
-- 其它：点击卡片把对应 URL 交给 `UrlOpener`；点「提交网站」没有任何反应；卡片渲染首字母、名称与描述，悬停上浮量等于 `AppSizes.cardHoverLift`。
+- 其它：点击卡片把对应 URL 交给 `UrlOpener`；点「提交网站」跳到后端配的地址；卡片渲染首字母、名称与描述，悬停上浮量等于 `AppSizes.cardHoverLift`。
 - 后端对接：请求打到 `/api/nav`；分组映射成侧栏导航树；只有挂着网站的分组进内容区；
   子分组标题带父级前缀；网站顺序按后端给的排；非 200、非 JSON、缺 `groups`、
   连不上后端分别给出对应提示；缺字段的单条数据被跳过而不是整页失败。
 - 加载状态：数据没回来时显示「正在加载…」；失败时显示原因和「重试」；点重试会重新取数并在成功后渲染内容。
-- 提交表单：空表单提交会逐项提示且不发请求；内网地址被拦下；合法内容按 camelCase
-  字段发给仓库；后端报错时留在表单里显示原话；提交中按钮变「提交中…」且不可再点；
-  模板里只列用户分组（内置分组不出现在建议里），点建议会填进输入框。
-- 联调：点侧栏「提交网站」打开表单；提交成功后静默重新拉一次数据并弹提示。
-- 编辑 / 删除：可修改的条目才有入口；编辑表单预填现有内容且不显示提交者字段；
-  删除要先确认，点取消什么都不发生；确认后调删除接口并静默刷新；内置条目没有这两个入口。
-- 站点信息：站点名与搜索框提示来自后端 `site` 字段，前端不再写死。
+- 站点信息：站点名、搜索框提示、提交入口地址都来自后端 `site` 字段，前端不再写死。
 
 ## 10. 后续演进建议
 
diff --git a/docs/submit-site-form.md b/docs/submit-site-form.md
deleted file mode 100644
index 60d4a2a..0000000
--- a/docs/submit-site-form.md
+++ /dev/null
@@ -1,116 +0,0 @@
-# 提交网站表单设计
-
-> 已按本文实现（含「错误色 / 可点建议 / 提交后刷新」三条确认）。代码在
-> `frontend/lib/features/home/presentation/widgets/submit_site_dialog.dart`。
-> 实现与本文有几处按实际取舍收敛，差异记在第 8 节。
-
-## 1. 目标与约束
-
-- 入口：侧栏底部的「提交网站」按钮（现在是个空按钮）。原型里没有这个表单，
-  所以这里定完之后再动手写。
-- 只管**用户提交**这一条路（`POST /api/sites`）。接口推送是给第三方用的，
-  走令牌，不在页面上暴露。
-- **表单里没有「选择分组」这个动作**：后端不接受 `categoryId`，只接受分组名，
-  而且提交的内容永远不会落进内置分组。表单要顺着这个规则设计，
-  不能让用户以为可以把站点塞进「常用推荐」「素材资源」这些内置分组。
-- 视觉只能用现有设计令牌（`index3.html` 那套），不引入新的配色和圆角体系。
-
-## 2. 交互流程
-
-```
-点侧栏「提交网站」
-   │
-   ▼
-弹出对话框（遮罩 + 白底卡片，居中）
-   │  填写（改动某个字段时清掉它上一次的错误）
-   ▼
-点「提交」
-   ├─ 有字段不合格 → 定位到第一个不合格的字段并提示，不发请求
-   └─ 都合格 → 按钮进入「提交中…」，禁用整张表单
-         ├─ 201 → 关掉对话框 + 顶部提示「已提交，感谢」+ 重新拉一次 /api/nav
-         └─ 其它 → 留在对话框里，顶部显示后端返回的原因，可以改了再提交
-```
-
-关闭方式：右上角 ×、点遮罩、「取消」按钮、Esc 键。提交中不允许关闭（避免请求还没回来
-就把界面收了）。
-
-## 3. 字段定义
-
-字段与后端 `POST /api/sites` 的入参一一对应，校验规则也和后端保持一致——
-前端先拦一遍是为了即时反馈，后端那一遍才是权威。
-
-| 字段 | 控件 | 必填 | 限制 | 不合格时的提示 | 后端字段 |
-| --- | --- | --- | --- | --- | --- |
-| 网站名称 | 单行输入 | 是 | ≤ 60 字 | 请填写网站名称 / 网站名称最多 60 个字 | `title` |
-| 网站地址 | 单行输入 | 是 | 可解析的 http(s)，不能是本机或内网地址 | 请填写网站地址 / 地址要以 http:// 或 https:// 开头 / 不能填本机或内网地址 | `url` |
-| 一句话描述 | 多行输入（3 行） | 否 | ≤ 120 字 | 描述最多 120 个字 | `description` |
-| 分组 | 单行输入 | 是 | ≤ 30 字 | 请填写分组名称 | `group` |
-| 子分组 | 单行输入 | 否 | ≤ 30 字 | 子分组名称最多 30 个字 | `subGroup` |
-| 你的称呼或邮箱 | 单行输入 | 否 | ≤ 120 字 | 最多 120 个字 | `submittedBy` |
-
-### 3.1 分组与子分组怎么填
-
-- 两个都是**填名字**，不是选内置分类。placeholder 分别写：
-  「例如：AI 工具（会创建你自己的分组）」「例如：模型社区（可不填）」。
-- 分组下面给一行浅色说明：**「提交的网站会放在你自己的分组里，不会进内置分类。」**
-  这句话必须留着，否则用户会以为能提交到「常用推荐」。
-- 名字和已有的用户分组重名时会**复用**那个分组，不会重复创建——
-  所以两个输入框下面给一排可点的建议：分组建议列出现有用户分组，
-  子分组建议列出所选分组下已有的用户子分组（数据来自 `/api/nav` 里
-  `editable == true` 的分组）。点一下即填入，不想用就直接手打新名字。
-- 子分组留空表示直接放在一级分组下。
-
-## 4. 布局与视觉
-
-沿用现有令牌，不新增尺寸：
-
-| 部分 | 取值 |
-| --- | --- |
-| 遮罩 | `rgba(17, 24, 39, .45)` |
-| 卡片 | 白底 + 1px `#e2e8f0` 描边 + 12px 圆角 + `cardShadowHover` |
-| 卡片宽度 | 480px，两侧留 24px（窄屏时自适应） |
-| 卡片内边距 | 24px |
-| 标题 | 「提交网站」，`AppTextStyles.sectionTitle`，右侧一个 × 关闭按钮 |
-| 字段标签 | 13px，`--text-sub`，与输入框间隔 6px |
-| 输入框 | 复用搜索框那套：44px 高、1px 描边、12px 圆角、聚焦时主色边框 + 3px 光晕 |
-| 多行框 | 同上，高度 88px（3 行），垂直内边距 10px |
-| 字段间距 | 16px |
-| 底部按钮 | 右侧并排：`取消`（描边次级）+ `提交`（主色实底，8px 圆角——和侧栏「提交网站」一致） |
-| 字段错误文案 | 12px，紧随输入框下方，间隔 4px |
-
-## 5. 状态
-
-| 状态 | 表现 |
-| --- | --- |
-| 初始 | 所有输入为空，「提交」可点 |
-| 校验失败 | 不合格的字段旁显示提示，输入框边框变错误色；不发请求 |
-| 提交中 | 「提交」文案变「提交中…」并禁用，整张表单只读，× / 遮罩 / Esc 都不响应 |
-| 提交失败 | 卡片顶部一条错误条，显示后端 `{"error": "…"}` 里的原话；表单恢复可编辑 |
-| 提交成功 | 关闭卡片，弹一条「已提交，感谢」提示，并**静默**重新拉一次 `/api/nav`（不闪加载页） |
-
-## 6. 三点确认结果
-
-1. **错误色**：已新增 `AppColors.danger = #E5484D` 与它 8% 的叠加色
-   `dangerFaint`，只用在错误提示和错误边框上。
-2. **分组建议**：保留，做成可点胶囊；只列 `editable == true` 的分组，
-   内置分组不出现（点了也进不去）。
-3. **提交成功后刷新**：保留，用静默刷新——页面继续显示旧内容，
-   拉到新数据再整体替换，不会闪一下「正在加载」。
-
-## 7. 实现落点
-
-| 文件 | 职责 |
-| --- | --- |
-| `features/home/presentation/widgets/submit_site_dialog.dart` | 对话框本体：字段、校验提示、提交按钮 |
-| `features/home/data/home_repository.dart` | 契约加一个 `submitSite(...)` |
-| `features/home/data/http_home_repository.dart` | 实现：`POST /api/sites`，把后端的中文错误原样抛给界面 |
-| `features/home/data/mock_home_repository.dart` | 测试用：记录调用，不真的发请求 |
-| `features/home/presentation/pages/home_page.dart` | 「提交网站」按钮改为打开对话框；成功后静默重新取数并提示 |
-
-## 8. 实现与本文的差异
-
-| 本文原写法 | 实际实现 | 原因 |
-| --- | --- | --- |
-| 失焦时校验 | 提交时统一校验，改动字段时清掉该字段的错误 | 少一套焦点状态，行为对用户更可预期 |
-| 底部按钮是「主色胶囊」 | 主色实底 + 8px 圆角 | `index3.html` 的调色板里没有胶囊圆角，侧栏「提交网站」也是 8px |
-| 成功提示在页面顶部 | 底部提示条（`SnackBar`） | 复用主题里已经配好的提示条，不新增一套浮层 |
diff --git a/frontend/README.md b/frontend/README.md
index ef998da..7b70655 100644
--- a/frontend/README.md
+++ b/frontend/README.md
@@ -23,14 +23,14 @@ flutter build web --dart-define=NAVIUS_API_BASE=https://api.example.com
 
 后端没起来时页面会显示「加载失败」和具体原因，并给一个「重试」按钮。
 
-侧栏底部的「提交网站」会打开提交表单：填完直接进后端的用户分组（不需要审核），
-提交成功后页面会静默重新拉一次数据，新站点立刻出现在侧栏里。
+侧栏底部的「提交网站」直接跳到后端配好的收集入口（`nav.json` 的 `site.submitUrl`，
+填 Mattermost 地址即可）。页面上不再有提交表单——收集和讨论都在 Mattermost 里做，
+网站数据由后端接口写入。
 
-用户提交 / 接口推送进来的站点（后端返回的 `editable == true`）在卡片悬停时右上角
-会露出「编辑 / 删除」：编辑复用同一个表单（预填现有内容）走 `PATCH`，
-删除会先确认再走 `DELETE`，两个操作成功后都会静默刷新。系统内置的卡片没有这两个入口。
+**页面上没有编辑和删除入口**：卡片只管展示和跳转，用户提交的站点照样由后端接口
+（`PATCH` / `DELETE`）维护，只是不从这里操作。
 
-站点名和搜索框提示也来自后端（`data/site.json`），前端不再写死。
+站点名、搜索框提示、提交入口地址都来自后端（`nav.json` 的 `site`），前端不再写死。
 
 ## 常用命令
 
@@ -60,8 +60,8 @@ flutter build web          # 构建产物输出到 build/web
 - mock 实现：`lib/features/home/data/mock_home_repository.dart`（测试用）
 
 接口对应关系：读 `GET /api/nav`、提交 `POST /api/sites`、编辑 `PATCH /api/sites/{id}`、
-删除 `DELETE /api/sites/{id}`。表单在 `presentation/widgets/site_form_dialog.dart`
-（新增和编辑共用），设计见 [docs/submit-site-form.md](../docs/submit-site-form.md)。
+删除 `DELETE /api/sites/{id}`。仓库契约里四个方法都在，界面目前只用到「读」和
+「跳转到提交入口」，另外三个留给后台工具或以后再做界面时用。
 
 接口返回的分组树在 `http_home_repository.dart` 里映射成前端模型：分组变成侧栏导航，
 **只有挂着网站的分组才进内容区**（空分组留在侧栏，点了没有对应内容——和原型一致），
diff --git a/frontend/lib/core/constants/app_sizes.dart b/frontend/lib/core/constants/app_sizes.dart
index 121fb69..7477c52 100644
--- a/frontend/lib/core/constants/app_sizes.dart
+++ b/frontend/lib/core/constants/app_sizes.dart
@@ -155,33 +155,6 @@ abstract final class AppSizes {
   /// 悬停时上移距离（`translateY(-3px)`）。
   static const double backToTopHoverLift = 3;
 
-  // ---- 通用间距 ----
-  //
-  // 上面的常量按「用在哪」命名；表单这类地方间距是通用的，
-  // 这里给一套通用刻度，避免在组件里写裸数字。
-  static const double spaceXs = 4;
-  static const double spaceSm = 8;
-  static const double spaceMd = 12;
-  static const double spaceLg = 16;
-  static const double spaceXl = 24;
-
-  // ---- 表单 ----
-
-  /// 对话框内边距。
-  static const double dialogPadding = 24;
-
-  /// 对话框最大宽度。
-  static const double dialogMaxWidth = 480;
-
-  /// 字段标签与输入框之间的间距。
-  static const double fieldLabelGap = 6;
-
-  /// 多行输入框高度（3 行）。
-  static const double fieldMultilineHeight = 88;
-
-  /// 对话框右上角关闭按钮的点击热区。
-  static const double iconButtonSize = 28;
-
   // ---- 通用 ----
 
   /// 通用过渡时长（CSS 里的 `transition: 0.2s`）。
diff --git a/frontend/lib/features/home/data/http_home_repository.dart b/frontend/lib/features/home/data/http_home_repository.dart
index 2e0fd62..ff8d3ec 100644
--- a/frontend/lib/features/home/data/http_home_repository.dart
+++ b/frontend/lib/features/home/data/http_home_repository.dart
@@ -149,6 +149,7 @@ HomeData _toHomeData(List<Object?> groups, Map<String, dynamic> siteMeta) {
     searchHint: siteMeta['searchHint'] as String? ?? _fallbackSearchHint,
     navNodes: navNodes,
     sections: sections,
+    submitUrl: siteMeta['submitUrl'] as String? ?? '',
   );
 }
 
diff --git a/frontend/lib/features/home/data/mock_home_data.dart b/frontend/lib/features/home/data/mock_home_data.dart
index 05d8ce7..ee54cf1 100644
--- a/frontend/lib/features/home/data/mock_home_data.dart
+++ b/frontend/lib/features/home/data/mock_home_data.dart
@@ -80,4 +80,5 @@ const HomeData mockHomeData = HomeData(
   searchHint: '输入关键字搜索全网资源...',
   navNodes: mockNavNodes,
   sections: mockLinkSections,
+  submitUrl: 'https://mattermost.example.com',
 );
diff --git a/frontend/lib/features/home/domain/models/home_data.dart b/frontend/lib/features/home/domain/models/home_data.dart
index 272621f..0d7ec03 100644
--- a/frontend/lib/features/home/domain/models/home_data.dart
+++ b/frontend/lib/features/home/domain/models/home_data.dart
@@ -12,6 +12,7 @@ class HomeData {
     required this.searchHint,
     required this.navNodes,
     required this.sections,
+    this.submitUrl = '',
   });
 
   /// 站点名，显示在侧栏顶部与浏览器标题。
@@ -20,6 +21,11 @@ class HomeData {
   /// 搜索框占位文案。
   final String searchHint;
 
+  /// 「提交网站」跳转的地址（Mattermost 之类的收集入口），来自后端 `site.submitUrl`。
+  ///
+  /// 为空表示后端没配，点了就不做任何事。
+  final String submitUrl;
+
   /// 侧栏导航树。
   final List<NavNode> navNodes;
 
diff --git a/frontend/lib/features/home/presentation/pages/home_page.dart b/frontend/lib/features/home/presentation/pages/home_page.dart
index a90a999..b61fcf0 100644
--- a/frontend/lib/features/home/presentation/pages/home_page.dart
+++ b/frontend/lib/features/home/presentation/pages/home_page.dart
@@ -10,13 +10,9 @@ import '../../data/home_repository.dart';
 import '../../domain/models/home_data.dart';
 import '../../domain/models/link_item.dart';
 import '../../domain/models/link_section.dart';
-import '../../domain/models/nav_node.dart';
-import '../../domain/models/submit_site_draft.dart';
 import '../widgets/back_to_top_button.dart';
-import '../widgets/confirm_dialog.dart';
 import '../widgets/link_section_view.dart';
 import '../widgets/sidebar_nav.dart';
-import '../widgets/site_form_dialog.dart';
 import '../widgets/top_bar.dart';
 
 /// 首页：可折叠侧栏 + 顶部控制栏 + 分组卡片网格。
@@ -153,100 +149,14 @@ class _HomePageState extends State<HomePage> {
 
   void _openItem(LinkItem item) => widget.urlOpener.open(item.url);
 
-  /// 打开「提交网站」表单；提交成功后静默刷新一次，让新站点立刻出现在侧栏里。
-  Future<void> _openSubmitDialog(HomeData data) async {
-    final bool saved = await showSiteFormDialog(
-      context: context,
-      navNodes: data.navNodes,
-      heading: '提交网站',
-      onSubmit: (SubmitSiteDraft draft) => widget.repository.submitSite(draft),
-    );
-    if (!saved || !mounted) {
-      return;
-    }
-    _toast('已提交，感谢');
-    await _load(showLoading: false);
-  }
-
-  /// 编辑一个用户提交的站点：表单预填现有内容，保存走 `PATCH /api/sites/{id}`。
-  Future<void> _openEditDialog(HomeData data, LinkItem item) async {
-    final ({String group, String subGroup})? path = _groupPathOf(
-      data.navNodes,
-      item.categoryId,
-    );
-    final bool saved = await showSiteFormDialog(
-      context: context,
-      navNodes: data.navNodes,
-      heading: '编辑网站',
-      initial: SubmitSiteDraft(
-        title: item.title,
-        url: item.url,
-        description: item.description,
-        group: path?.group ?? '',
-        subGroup: path?.subGroup ?? '',
-      ),
-      onSubmit: (SubmitSiteDraft draft) =>
-          widget.repository.updateSite(item.id, draft),
-    );
-    if (!saved || !mounted) {
-      return;
-    }
-    _toast('已保存');
-    await _load(showLoading: false);
-  }
-
-  /// 删除一个用户提交的站点：先确认，再走 `DELETE /api/sites/{id}`。
-  Future<void> _confirmDelete(LinkItem item) async {
-    final bool confirmed = await showConfirmDialog(
-      context: context,
-      title: '删除网站',
-      message: '确定要删除「${item.title}」吗？删掉之后不能恢复。',
-      confirmLabel: '删除',
-      danger: true,
-    );
-    if (!confirmed || !mounted) {
-      return;
-    }
-    try {
-      await widget.repository.deleteSite(item.id);
-    } catch (error) {
-      if (mounted) {
-        _toast('删除失败：$error');
-      }
-      return;
-    }
-    if (!mounted) {
-      return;
-    }
-    _toast('已删除');
-    await _load(showLoading: false);
-  }
-
-  void _toast(String message) {
-    ScaffoldMessenger.of(
-      context,
-    ).showSnackBar(SnackBar(content: Text(message)));
-  }
-
-  /// 从侧栏树里反查某个分组 id 的「一级分组 + 子分组」名字。
+  /// 「提交网站」跳到后端配好的收集入口（Mattermost 之类）。
   ///
-  /// 后端只按分组名收更新，所以编辑时必须把 id 还原成名字；
-  /// 层级最多两级，这里只查两轮。
-  ({String group, String subGroup})? _groupPathOf(
-    List<NavNode> nodes,
-    String categoryId,
-  ) {
-    for (final NavNode root in nodes) {
-      if (root.id == categoryId) {
-        return (group: root.title, subGroup: '');
-      }
-      for (final NavNode child in root.children) {
-        if (child.id == categoryId) {
-          return (group: root.title, subGroup: child.title);
-        }
-      }
+  /// 地址在 `data/nav.json` 的 `site.submitUrl`；没配就什么都不做。
+  void _openSubmitUrl(HomeData data) {
+    if (data.submitUrl.isEmpty) {
+      return;
     }
-    return null;
+    widget.urlOpener.open(data.submitUrl);
   }
 
   void _backToTop() {
@@ -293,7 +203,7 @@ class _HomePageState extends State<HomePage> {
               openGroupIds: _openGroupIds,
               onToggleGroup: _toggleGroup,
               onSectionSelected: _goToSection,
-              onSubmitSite: () => unawaited(_openSubmitDialog(data)),
+              onSubmitSite: () => _openSubmitUrl(data),
               onToggleCollapse: _toggleSidebar,
             ),
             Expanded(child: _buildMain(data)),
@@ -334,9 +244,6 @@ class _HomePageState extends State<HomePage> {
                 key: _sectionKeys[section.id],
                 section: section,
                 onOpen: _openItem,
-                onEdit: (LinkItem item) =>
-                    unawaited(_openEditDialog(data, item)),
-                onDelete: (LinkItem item) => unawaited(_confirmDelete(item)),
               ),
             ),
         ],
diff --git a/frontend/lib/features/home/presentation/widgets/confirm_dialog.dart b/frontend/lib/features/home/presentation/widgets/confirm_dialog.dart
deleted file mode 100644
index ecc3362..0000000
--- a/frontend/lib/features/home/presentation/widgets/confirm_dialog.dart
+++ /dev/null
@@ -1,91 +0,0 @@
-import 'package:flutter/material.dart';
-
-import '../../../../core/constants/app_sizes.dart';
-import '../../../../core/theme/app_colors.dart';
-import '../../../../core/theme/app_text_styles.dart';
-import 'dialog_buttons.dart';
-
-/// 通用确认框，返回 true 表示用户点了确认。
-///
-/// [danger] 为 true 时确认按钮用错误色，用在删除这类不可逆操作上。
-Future<bool> showConfirmDialog({
-  required BuildContext context,
-  required String title,
-  required String message,
-  required String confirmLabel,
-  String cancelLabel = '取消',
-  bool danger = false,
-}) async {
-  final bool? confirmed = await showDialog<bool>(
-    context: context,
-    barrierColor: const Color(0x73111827),
-    builder: (BuildContext context) => _ConfirmDialog(
-      title: title,
-      message: message,
-      confirmLabel: confirmLabel,
-      cancelLabel: cancelLabel,
-      danger: danger,
-    ),
-  );
-  return confirmed ?? false;
-}
-
-class _ConfirmDialog extends StatelessWidget {
-  const _ConfirmDialog({
-    required this.title,
-    required this.message,
-    required this.confirmLabel,
-    required this.cancelLabel,
-    required this.danger,
-  });
-
-  final String title;
-  final String message;
-  final String confirmLabel;
-  final String cancelLabel;
-  final bool danger;
-
-  @override
-  Widget build(BuildContext context) {
-    return Dialog(
-      backgroundColor: Colors.transparent,
-      elevation: 0,
-      insetPadding: const EdgeInsets.all(AppSizes.dialogPadding),
-      child: Container(
-        constraints: const BoxConstraints(maxWidth: 360),
-        decoration: BoxDecoration(
-          color: AppColors.surface,
-          border: Border.all(color: AppColors.border),
-          borderRadius: BorderRadius.circular(AppSizes.cardRadius),
-          boxShadow: AppColors.cardShadowHover,
-        ),
-        padding: const EdgeInsets.all(AppSizes.dialogPadding),
-        child: Column(
-          mainAxisSize: MainAxisSize.min,
-          crossAxisAlignment: CrossAxisAlignment.start,
-          children: <Widget>[
-            Text(title, style: AppTextStyles.sectionTitle),
-            const SizedBox(height: AppSizes.spaceSm),
-            Text(message, style: AppTextStyles.emptyMessage),
-            const SizedBox(height: AppSizes.spaceXl),
-            Row(
-              mainAxisAlignment: MainAxisAlignment.end,
-              children: <Widget>[
-                DialogGhostButton(
-                  label: cancelLabel,
-                  onTap: () => Navigator.of(context).pop(false),
-                ),
-                const SizedBox(width: AppSizes.spaceMd),
-                DialogPrimaryButton(
-                  label: confirmLabel,
-                  danger: danger,
-                  onTap: () => Navigator.of(context).pop(true),
-                ),
-              ],
-            ),
-          ],
-        ),
-      ),
-    );
-  }
-}
diff --git a/frontend/lib/features/home/presentation/widgets/dialog_buttons.dart b/frontend/lib/features/home/presentation/widgets/dialog_buttons.dart
deleted file mode 100644
index 7d1f4a3..0000000
--- a/frontend/lib/features/home/presentation/widgets/dialog_buttons.dart
+++ /dev/null
@@ -1,117 +0,0 @@
-import 'package:flutter/material.dart';
-
-import '../../../../core/constants/app_sizes.dart';
-import '../../../../core/theme/app_colors.dart';
-import '../../../../core/theme/app_text_styles.dart';
-
-/// 对话框里的主按钮：实底、8px 圆角（和侧栏「提交网站」一致）。
-///
-/// [danger] 为 true 时用错误色，用在「删除」这类不可逆操作上。
-class DialogPrimaryButton extends StatefulWidget {
-  const DialogPrimaryButton({
-    super.key,
-    required this.label,
-    required this.onTap,
-    this.danger = false,
-  });
-
-  /// 按钮文字。
-  final String label;
-
-  /// 点击回调；为 null 表示禁用。
-  final VoidCallback? onTap;
-
-  /// 是否用错误色（删除类操作）。
-  final bool danger;
-
-  @override
-  State<DialogPrimaryButton> createState() => _DialogPrimaryButtonState();
-}
-
-class _DialogPrimaryButtonState extends State<DialogPrimaryButton> {
-  bool _hovered = false;
-
-  @override
-  Widget build(BuildContext context) {
-    final bool enabled = widget.onTap != null;
-    final Color background = widget.danger
-        ? AppColors.danger
-        : AppColors.primary;
-
-    return MouseRegion(
-      cursor: enabled ? SystemMouseCursors.click : SystemMouseCursors.basic,
-      onEnter: (_) => setState(() => _hovered = true),
-      onExit: (_) => setState(() => _hovered = false),
-      child: GestureDetector(
-        onTap: widget.onTap,
-        child: AnimatedContainer(
-          duration: AppSizes.transition,
-          padding: const EdgeInsets.symmetric(
-            horizontal: AppSizes.cardPaddingHorizontal,
-            vertical: 10,
-          ),
-          decoration: BoxDecoration(
-            color: enabled ? background : AppColors.border,
-            borderRadius: BorderRadius.circular(AppSizes.navItemRadius),
-          ),
-          child: Text(
-            widget.label,
-            style: AppTextStyles.submitButton.copyWith(
-              color: enabled ? AppColors.surface : AppColors.textSecondary,
-              fontWeight: _hovered ? FontWeight.w600 : FontWeight.w500,
-            ),
-          ),
-        ),
-      ),
-    );
-  }
-}
-
-/// 对话框里的次级按钮：描边、透明底。
-class DialogGhostButton extends StatefulWidget {
-  const DialogGhostButton({super.key, required this.label, required this.onTap});
-
-  /// 按钮文字。
-  final String label;
-
-  /// 点击回调；为 null 表示禁用。
-  final VoidCallback? onTap;
-
-  @override
-  State<DialogGhostButton> createState() => _DialogGhostButtonState();
-}
-
-class _DialogGhostButtonState extends State<DialogGhostButton> {
-  bool _hovered = false;
-
-  @override
-  Widget build(BuildContext context) {
-    final bool enabled = widget.onTap != null;
-    return MouseRegion(
-      cursor: enabled ? SystemMouseCursors.click : SystemMouseCursors.basic,
-      onEnter: (_) => setState(() => _hovered = true),
-      onExit: (_) => setState(() => _hovered = false),
-      child: GestureDetector(
-        onTap: widget.onTap,
-        child: AnimatedContainer(
-          duration: AppSizes.transition,
-          padding: const EdgeInsets.symmetric(
-            horizontal: AppSizes.cardPaddingHorizontal,
-            vertical: 9,
-          ),
-          decoration: BoxDecoration(
-            color: _hovered ? AppColors.primaryFaint : Colors.transparent,
-            border: Border.all(color: AppColors.border),
-            borderRadius: BorderRadius.circular(AppSizes.navItemRadius),
-          ),
-          child: Text(
-            widget.label,
-            style: AppTextStyles.submitButton.copyWith(
-              color: enabled ? AppColors.textSecondary : AppColors.navArrow,
-            ),
-          ),
-        ),
-      ),
-    );
-  }
-}
diff --git a/frontend/lib/features/home/presentation/widgets/link_card.dart b/frontend/lib/features/home/presentation/widgets/link_card.dart
index 3a2db14..40bace6 100644
--- a/frontend/lib/features/home/presentation/widgets/link_card.dart
+++ b/frontend/lib/features/home/presentation/widgets/link_card.dart
@@ -8,16 +8,8 @@ import '../../domain/models/link_item.dart';
 /// 站点卡片，对应 `index3.html` 里的 `.card`。
 ///
 /// 结构是「36px 的字母方块 + 名称 + 描述」，悬停时上移 2px 并加强阴影。
-/// 用户提交 / 接口推送进来的条目（`item.editable`）在悬停时右上角会露出
-/// 「编辑 / 删除」；系统内置的条目没有这两个按钮——后端也不允许改。
 class LinkCard extends StatefulWidget {
-  const LinkCard({
-    super.key,
-    required this.item,
-    required this.onOpen,
-    this.onEdit,
-    this.onDelete,
-  });
+  const LinkCard({super.key, required this.item, required this.onOpen});
 
   /// 站点数据。
   final LinkItem item;
@@ -25,12 +17,6 @@ class LinkCard extends StatefulWidget {
   /// 打开回调。
   final VoidCallback onOpen;
 
-  /// 编辑回调；为空或条目不可修改时不显示编辑按钮。
-  final VoidCallback? onEdit;
-
-  /// 删除回调；为空或条目不可修改时不显示删除按钮。
-  final VoidCallback? onDelete;
-
   @override
   State<LinkCard> createState() => _LinkCardState();
 }
@@ -40,8 +26,6 @@ class _LinkCardState extends State<LinkCard> {
 
   @override
   Widget build(BuildContext context) {
-    final bool canManage = widget.item.editable;
-
     return MouseRegion(
       cursor: SystemMouseCursors.click,
       onEnter: (_) => setState(() => _hovered = true),
@@ -69,68 +53,31 @@ class _LinkCardState extends State<LinkCard> {
                 ? AppColors.cardShadowHover
                 : AppColors.cardShadow,
           ),
-          child: Stack(
+          child: Row(
             children: <Widget>[
-              Row(
-                children: <Widget>[
-                  _CardIcon(initial: widget.item.initial),
-                  const SizedBox(width: AppSizes.cardIconGap),
-                  Expanded(
-                    child: Column(
-                      crossAxisAlignment: CrossAxisAlignment.start,
-                      mainAxisSize: MainAxisSize.min,
-                      children: <Widget>[
-                        Text(
-                          widget.item.title,
-                          style: AppTextStyles.cardTitle,
-                          maxLines: 1,
-                          overflow: TextOverflow.ellipsis,
-                        ),
-                        const SizedBox(height: AppSizes.cardTitleGap),
-                        Text(
-                          widget.item.description,
-                          style: AppTextStyles.cardDesc,
-                          maxLines: 1,
-                          overflow: TextOverflow.ellipsis,
-                        ),
-                      ],
+              _CardIcon(initial: widget.item.initial),
+              const SizedBox(width: AppSizes.cardIconGap),
+              Expanded(
+                child: Column(
+                  crossAxisAlignment: CrossAxisAlignment.start,
+                  mainAxisSize: MainAxisSize.min,
+                  children: <Widget>[
+                    Text(
+                      widget.item.title,
+                      style: AppTextStyles.cardTitle,
+                      maxLines: 1,
+                      overflow: TextOverflow.ellipsis,
                     ),
-                  ),
-                ],
-              ),
-              // 悬停才露出来，且不占正文的位置：不给可修改的卡片留常驻空白，
-              // 也不让鼠标移上去时文字宽度跳一下。
-              if (canManage)
-                Positioned(
-                  right: 0,
-                  top: 0,
-                  child: AnimatedOpacity(
-                    duration: AppSizes.transition,
-                    opacity: _hovered ? 1 : 0,
-                    child: Row(
-                      mainAxisSize: MainAxisSize.min,
-                      children: <Widget>[
-                        if (widget.onEdit != null)
-                          _CardAction(
-                            icon: '✎',
-                            tooltip: '编辑',
-                            background: AppColors.surface,
-                            onTap: widget.onEdit!,
-                          ),
-                        if (widget.onEdit != null && widget.onDelete != null)
-                          const SizedBox(width: AppSizes.spaceXs),
-                        if (widget.onDelete != null)
-                          _CardAction(
-                            icon: '✕',
-                            tooltip: '删除',
-                            background: AppColors.surface,
-                            danger: true,
-                            onTap: widget.onDelete!,
-                          ),
-                      ],
+                    const SizedBox(height: AppSizes.cardTitleGap),
+                    Text(
+                      widget.item.description,
+                      style: AppTextStyles.cardDesc,
+                      maxLines: 1,
+                      overflow: TextOverflow.ellipsis,
                     ),
-                  ),
+                  ],
                 ),
+              ),
             ],
           ),
         ),
@@ -139,69 +86,6 @@ class _LinkCardState extends State<LinkCard> {
   }
 }
 
-/// 卡片右上角的小动作按钮（编辑 / 删除）。
-class _CardAction extends StatefulWidget {
-  const _CardAction({
-    required this.icon,
-    required this.tooltip,
-    required this.background,
-    required this.onTap,
-    this.danger = false,
-  });
-
-  final String icon;
-  final String tooltip;
-  final Color background;
-  final VoidCallback onTap;
-  final bool danger;
-
-  @override
-  State<_CardAction> createState() => _CardActionState();
-}
-
-class _CardActionState extends State<_CardAction> {
-  bool _hovered = false;
-
-  @override
-  Widget build(BuildContext context) {
-    final Color foreground = _hovered
-        ? (widget.danger ? AppColors.danger : AppColors.primary)
-        : AppColors.navArrow;
-
-    return Tooltip(
-      message: widget.tooltip,
-      child: MouseRegion(
-        cursor: SystemMouseCursors.click,
-        onEnter: (_) => setState(() => _hovered = true),
-        onExit: (_) => setState(() => _hovered = false),
-        child: GestureDetector(
-          // 只处理自己的点击，不要让卡片把事件吃掉（否则会去打开网站）。
-          onTap: widget.onTap,
-          child: AnimatedContainer(
-            duration: AppSizes.transition,
-            width: AppSizes.iconButtonSize,
-            height: AppSizes.iconButtonSize,
-            alignment: Alignment.center,
-            decoration: BoxDecoration(
-              color: _hovered
-                  ? (widget.danger
-                        ? AppColors.dangerFaint
-                        : AppColors.primaryFaint)
-                  : widget.background,
-              border: Border.all(color: AppColors.border),
-              borderRadius: BorderRadius.circular(AppSizes.navItemRadius),
-            ),
-            child: Text(
-              widget.icon,
-              style: AppTextStyles.cardDesc.copyWith(color: foreground),
-            ),
-          ),
-        ),
-      ),
-    );
-  }
-}
-
 /// 卡片左侧的字母方块（`.card-icon`）。
 class _CardIcon extends StatelessWidget {
   const _CardIcon({required this.initial});
diff --git a/frontend/lib/features/home/presentation/widgets/link_section_view.dart b/frontend/lib/features/home/presentation/widgets/link_section_view.dart
index 39834f6..8849dcb 100644
--- a/frontend/lib/features/home/presentation/widgets/link_section_view.dart
+++ b/frontend/lib/features/home/presentation/widgets/link_section_view.dart
@@ -14,8 +14,6 @@ class LinkSectionView extends StatelessWidget {
     super.key,
     required this.section,
     required this.onOpen,
-    this.onEdit,
-    this.onDelete,
   });
 
   /// 分组数据。
@@ -24,12 +22,6 @@ class LinkSectionView extends StatelessWidget {
   /// 打开某个站点。
   final ValueChanged<LinkItem> onOpen;
 
-  /// 编辑某个站点；为空时卡片不显示编辑入口。
-  final ValueChanged<LinkItem>? onEdit;
-
-  /// 删除某个站点；为空时卡片不显示删除入口。
-  final ValueChanged<LinkItem>? onDelete;
-
   @override
   Widget build(BuildContext context) {
     return Column(
@@ -55,12 +47,7 @@ class LinkSectionView extends StatelessWidget {
                 for (final LinkItem item in section.items)
                   SizedBox(
                     width: itemWidth,
-                    child: LinkCard(
-                      item: item,
-                      onOpen: () => onOpen(item),
-                      onEdit: onEdit == null ? null : () => onEdit!(item),
-                      onDelete: onDelete == null ? null : () => onDelete!(item),
-                    ),
+                    child: LinkCard(item: item, onOpen: () => onOpen(item)),
                   ),
               ],
             );
diff --git a/frontend/lib/features/home/presentation/widgets/site_form_dialog.dart b/frontend/lib/features/home/presentation/widgets/site_form_dialog.dart
deleted file mode 100644
index a7bdb66..0000000
--- a/frontend/lib/features/home/presentation/widgets/site_form_dialog.dart
+++ /dev/null
@@ -1,757 +0,0 @@
-import 'package:flutter/material.dart';
-
-import '../../../../core/constants/app_sizes.dart';
-import '../../../../core/theme/app_colors.dart';
-import '../../../../core/theme/app_text_styles.dart';
-import '../../../../core/utils/text.dart';
-import '../../domain/models/nav_node.dart';
-import '../../domain/models/submit_site_draft.dart';
-import 'dialog_buttons.dart';
-
-/// 打开网站表单对话框，返回 true 表示保存成功了。
-///
-/// 新增和编辑共用这一个表单：新增时 [onSubmit] 打 `POST /api/sites`，
-/// 编辑时打 `PATCH /api/sites/{id}`，并用 [initial] 预填现有内容。
-Future<bool> showSiteFormDialog({
-  required BuildContext context,
-  required List<NavNode> navNodes,
-  required String heading,
-  required Future<void> Function(SubmitSiteDraft draft) onSubmit,
-  SubmitSiteDraft? initial,
-}) async {
-  final bool? submitted = await showDialog<bool>(
-    context: context,
-    barrierColor: const Color(0x73111827),
-    builder: (BuildContext context) => SiteFormDialog(
-      navNodes: navNodes,
-      heading: heading,
-      onSubmit: onSubmit,
-      initial: initial,
-    ),
-  );
-  return submitted ?? false;
-}
-
-/// 网站表单（新增 / 编辑）。
-///
-/// 字段与后端 `POST /api/sites` 一一对应：**没有「选择分组」这个动作**，
-/// 只有分组名——后端只会在用户创建的分组里查找或新建，提交的内容永远进不了
-/// 内置分组，所以界面上也要把这件事说清楚，并只给用户分组的建议。
-class SiteFormDialog extends StatefulWidget {
-  const SiteFormDialog({
-    super.key,
-    required this.navNodes,
-    required this.heading,
-    required this.onSubmit,
-    this.initial,
-  });
-
-  /// 侧栏那棵树，用来给出「已有的用户分组」建议。
-  final List<NavNode> navNodes;
-
-  /// 对话框标题，例如「提交网站」或「编辑网站」。
-  final String heading;
-
-  /// 保存动作。抛异常时表单会留在原地并显示原因。
-  final Future<void> Function(SubmitSiteDraft draft) onSubmit;
-
-  /// 编辑时的现有内容；新增时为 null。
-  final SubmitSiteDraft? initial;
-
-  @override
-  State<SiteFormDialog> createState() => _SiteFormDialogState();
-}
-
-class _SiteFormDialogState extends State<SiteFormDialog> {
-  late final TextEditingController _title;
-  late final TextEditingController _url;
-  late final TextEditingController _description;
-  late final TextEditingController _group;
-  late final TextEditingController _subGroup;
-  late final TextEditingController _submittedBy;
-
-  Map<String, String?> _errors = <String, String?>{};
-  String? _serverError;
-  bool _submitting = false;
-
-  @override
-  void initState() {
-    super.initState();
-    final SubmitSiteDraft? initial = widget.initial;
-    _title = TextEditingController(text: initial?.title ?? '');
-    _url = TextEditingController(text: initial?.url ?? '');
-    _description = TextEditingController(text: initial?.description ?? '');
-    _group = TextEditingController(text: initial?.group ?? '');
-    _subGroup = TextEditingController(text: initial?.subGroup ?? '');
-    _submittedBy = TextEditingController(text: initial?.submittedBy ?? '');
-  }
-
-  @override
-  void dispose() {
-    _title.dispose();
-    _url.dispose();
-    _description.dispose();
-    _group.dispose();
-    _subGroup.dispose();
-    _submittedBy.dispose();
-    super.dispose();
-  }
-
-  /// 已有的用户分组名（内置分组不出现在这里——选了也用不了）。
-  List<String> get _groupSuggestions => widget.navNodes
-      .where((NavNode node) => node.editable)
-      .map((NavNode node) => node.title)
-      .toList(growable: false);
-
-  /// 当前填的分组下已有的用户子分组。
-  List<String> get _subGroupSuggestions {
-    final String group = _group.text.trim();
-    for (final NavNode node in widget.navNodes) {
-      if (node.editable && node.title == group) {
-        return node.children
-            .where((NavNode child) => child.editable)
-            .map((NavNode child) => child.title)
-            .toList(growable: false);
-      }
-    }
-    return const <String>[];
-  }
-
-  /// 某个字段的内容变了：清掉它上一次的错误，让用户边改边看到反馈。
-  void _clearError(String field) {
-    if (_errors[field] == null && _serverError == null) {
-      return;
-    }
-    setState(() {
-      _errors = <String, String?>{..._errors, field: null};
-      _serverError = null;
-    });
-  }
-
-  Future<void> _submit() async {
-    final Map<String, String?> errors = <String, String?>{
-      'title': _validateTitle(_title.text),
-      'url': _validateUrl(_url.text),
-      'description': _validateDescription(_description.text),
-      'group': _validateGroup(_group.text),
-      'subGroup': _validateSubGroup(_subGroup.text),
-      'submittedBy': _validateSubmittedBy(_submittedBy.text),
-    };
-    setState(() {
-      _errors = errors;
-      _serverError = null;
-    });
-    if (errors.values.any((String? message) => message != null)) {
-      return;
-    }
-
-    setState(() => _submitting = true);
-    try {
-      await widget.onSubmit(
-        SubmitSiteDraft(
-          title: _title.text.trim(),
-          url: _url.text.trim(),
-          description: _description.text.trim(),
-          group: _group.text.trim(),
-          subGroup: _subGroup.text.trim(),
-          submittedBy: _submittedBy.text.trim(),
-        ),
-      );
-      if (!mounted) {
-        return;
-      }
-      Navigator.of(context).pop(true);
-    } catch (error) {
-      if (!mounted) {
-        return;
-      }
-      // 后端的中文说明原样显示，用户能看懂哪里不对。
-      setState(() {
-        _submitting = false;
-        _serverError = error.toString();
-      });
-    }
-  }
-
-  @override
-  Widget build(BuildContext context) {
-    return PopScope(
-      // 请求还在路上时不允许关闭：关了界面请求也回不来，用户会以为丢了。
-      canPop: !_submitting,
-      child: Dialog(
-        backgroundColor: Colors.transparent,
-        elevation: 0,
-        insetPadding: const EdgeInsets.all(AppSizes.dialogPadding),
-        child: Container(
-          constraints: const BoxConstraints(maxWidth: AppSizes.dialogMaxWidth),
-          decoration: BoxDecoration(
-            color: AppColors.surface,
-            border: Border.all(color: AppColors.border),
-            borderRadius: BorderRadius.circular(AppSizes.cardRadius),
-            boxShadow: AppColors.cardShadowHover,
-          ),
-          padding: const EdgeInsets.all(AppSizes.dialogPadding),
-          child: SingleChildScrollView(
-            child: Column(
-              mainAxisSize: MainAxisSize.min,
-              crossAxisAlignment: CrossAxisAlignment.stretch,
-              children: <Widget>[
-                _Header(
-                  heading: widget.heading,
-                  submitting: _submitting,
-                  onClose: () => Navigator.of(context).pop(false),
-                ),
-                if (_serverError != null) ...<Widget>[
-                  const SizedBox(height: AppSizes.spaceLg),
-                  _ErrorBanner(message: _serverError!),
-                ],
-                const SizedBox(height: AppSizes.spaceLg),
-                _InputBox(
-                  label: '网站名称',
-                  controller: _title,
-                  hint: '例如：GitHub',
-                  enabled: !_submitting,
-                  error: _errors['title'],
-                  onChanged: () => _clearError('title'),
-                ),
-                const SizedBox(height: AppSizes.spaceLg),
-                _InputBox(
-                  label: '网站地址',
-                  controller: _url,
-                  hint: 'https://…',
-                  enabled: !_submitting,
-                  error: _errors['url'],
-                  onChanged: () => _clearError('url'),
-                ),
-                const SizedBox(height: AppSizes.spaceLg),
-                _InputBox(
-                  label: '一句话描述',
-                  controller: _description,
-                  hint: '这个站点是做什么的（可不填）',
-                  enabled: !_submitting,
-                  error: _errors['description'],
-                  multiline: true,
-                  onChanged: () => _clearError('description'),
-                ),
-                const SizedBox(height: AppSizes.spaceLg),
-                _InputBox(
-                  label: '分组',
-                  controller: _group,
-                  hint: '例如：AI 工具',
-                  enabled: !_submitting,
-                  error: _errors['group'],
-                  onChanged: () {
-                    _clearError('group');
-                    // 分组一变，子分组建议跟着换。
-                    setState(() {});
-                  },
-                ),
-                const SizedBox(height: AppSizes.fieldLabelGap),
-                const Text(
-                  '提交的网站会放在你自己的分组里，不会进内置分类。',
-                  style: AppTextStyles.emptyMessage,
-                ),
-                if (_groupSuggestions.isNotEmpty) ...<Widget>[
-                  const SizedBox(height: AppSizes.spaceSm),
-                  _Suggestions(
-                    label: '已有的分组',
-                    values: _groupSuggestions,
-                    enabled: !_submitting,
-                    onPick: (String value) {
-                      _group.text = value;
-                      _clearError('group');
-                      setState(() {});
-                    },
-                  ),
-                ],
-                const SizedBox(height: AppSizes.spaceLg),
-                _InputBox(
-                  label: '子分组',
-                  controller: _subGroup,
-                  hint: '例如：模型社区（可不填）',
-                  enabled: !_submitting,
-                  error: _errors['subGroup'],
-                  onChanged: () => _clearError('subGroup'),
-                ),
-                if (_subGroupSuggestions.isNotEmpty) ...<Widget>[
-                  const SizedBox(height: AppSizes.spaceSm),
-                  _Suggestions(
-                    label: '已有的子分组',
-                    values: _subGroupSuggestions,
-                    enabled: !_submitting,
-                    onPick: (String value) {
-                      _subGroup.text = value;
-                      _clearError('subGroup');
-                      setState(() {});
-                    },
-                  ),
-                ],
-                // 编辑时不让改提交者：后端 PATCH 本来也不接受这个字段。
-                if (widget.initial == null) ...<Widget>[
-                  const SizedBox(height: AppSizes.spaceLg),
-                  _InputBox(
-                    label: '你的称呼或邮箱',
-                    controller: _submittedBy,
-                    hint: '可不填，方便回访时找你',
-                    enabled: !_submitting,
-                    error: _errors['submittedBy'],
-                    onChanged: () => _clearError('submittedBy'),
-                  ),
-                ],
-                const SizedBox(height: AppSizes.spaceXl),
-                _Actions(
-                  submitting: _submitting,
-                  onCancel: () => Navigator.of(context).pop(false),
-                  onSubmit: _submit,
-                ),
-              ],
-            ),
-          ),
-        ),
-      ),
-    );
-  }
-}
-
-/// 标题行：标题 + 关闭按钮。
-class _Header extends StatelessWidget {
-  const _Header({
-    required this.heading,
-    required this.submitting,
-    required this.onClose,
-  });
-
-  final String heading;
-  final bool submitting;
-  final VoidCallback onClose;
-
-  @override
-  Widget build(BuildContext context) {
-    return Row(
-      children: <Widget>[
-        Expanded(
-          child: Text(heading, style: AppTextStyles.sectionTitle),
-        ),
-        _IconButton(
-          icon: '×',
-          tooltip: '关闭',
-          onTap: submitting ? null : onClose,
-        ),
-      ],
-    );
-  }
-}
-
-/// 后端返回的失败说明，放在表单顶部。
-class _ErrorBanner extends StatelessWidget {
-  const _ErrorBanner({required this.message});
-
-  final String message;
-
-  @override
-  Widget build(BuildContext context) {
-    return Container(
-      padding: const EdgeInsets.symmetric(
-        horizontal: AppSizes.spaceMd,
-        vertical: 10,
-      ),
-      decoration: BoxDecoration(
-        color: AppColors.dangerFaint,
-        borderRadius: BorderRadius.circular(AppSizes.navItemRadius),
-      ),
-      child: Text(
-        message,
-        style: AppTextStyles.emptyMessage.copyWith(color: AppColors.danger),
-      ),
-    );
-  }
-}
-
-/// 带标签、错误提示的输入框。
-///
-/// 视觉复用搜索框那一套（44px 高 / 12px 圆角 / 聚焦光晕）：
-/// 输入框按自身行高定高，再用 Align 放进盒子里居中，不靠固定 padding 凑高度。
-class _InputBox extends StatefulWidget {
-  const _InputBox({
-    required this.label,
-    required this.controller,
-    required this.hint,
-    required this.enabled,
-    required this.onChanged,
-    this.error,
-    this.multiline = false,
-  });
-
-  final String label;
-  final TextEditingController controller;
-  final String hint;
-  final bool enabled;
-  final VoidCallback onChanged;
-  final String? error;
-  final bool multiline;
-
-  @override
-  State<_InputBox> createState() => _InputBoxState();
-}
-
-class _InputBoxState extends State<_InputBox> {
-  final FocusNode _focusNode = FocusNode();
-  bool _focused = false;
-
-  @override
-  void initState() {
-    super.initState();
-    _focusNode.addListener(_handleFocusChange);
-  }
-
-  @override
-  void dispose() {
-    _focusNode
-      ..removeListener(_handleFocusChange)
-      ..dispose();
-    super.dispose();
-  }
-
-  void _handleFocusChange() {
-    if (_focusNode.hasFocus != _focused) {
-      setState(() => _focused = _focusNode.hasFocus);
-    }
-  }
-
-  @override
-  Widget build(BuildContext context) {
-    final bool hasError = widget.error != null;
-    final Color borderColor = hasError
-        ? AppColors.danger
-        : (_focused ? AppColors.primary : AppColors.border);
-
-    final Widget field = TextField(
-      controller: widget.controller,
-      focusNode: _focusNode,
-      enabled: widget.enabled,
-      onChanged: (_) => widget.onChanged(),
-      maxLines: widget.multiline ? 3 : 1,
-      style: AppTextStyles.searchInput,
-      cursorColor: AppColors.primary,
-      decoration: InputDecoration(
-        isDense: true,
-        border: InputBorder.none,
-        contentPadding: EdgeInsets.zero,
-        hintText: widget.hint,
-        hintStyle: AppTextStyles.searchHint,
-      ),
-    );
-
-    return Column(
-      crossAxisAlignment: CrossAxisAlignment.start,
-      children: <Widget>[
-        Text(widget.label, style: AppTextStyles.emptyMessage),
-        const SizedBox(height: AppSizes.fieldLabelGap),
-        GestureDetector(
-          // 点盒子里输入框以外的留白也能聚焦。
-          onTap: widget.enabled ? _focusNode.requestFocus : null,
-          child: AnimatedContainer(
-            duration: AppSizes.transition,
-            curve: Curves.ease,
-            height: widget.multiline
-                ? AppSizes.fieldMultilineHeight
-                : AppSizes.searchHeight,
-            padding: EdgeInsets.symmetric(
-              horizontal: AppSizes.cardPaddingHorizontal,
-              vertical: widget.multiline ? 10 : 0,
-            ),
-            decoration: BoxDecoration(
-              color: widget.enabled ? AppColors.surface : AppColors.background,
-              border: Border.all(color: borderColor),
-              borderRadius: BorderRadius.circular(AppSizes.searchRadius),
-              // 聚焦时只剩光晕（原型 `.search-box:focus` 就是这个行为）。
-              boxShadow: <BoxShadow>[
-                if (_focused)
-                  const BoxShadow(color: AppColors.focusRing, spreadRadius: 3)
-                else if (hasError)
-                  const BoxShadow(
-                    color: AppColors.dangerFaint,
-                    spreadRadius: 3,
-                  )
-                else
-                  ...AppColors.cardShadow,
-              ],
-            ),
-            child: Align(
-              alignment: widget.multiline
-                  ? Alignment.topLeft
-                  : Alignment.centerLeft,
-              child: field,
-            ),
-          ),
-        ),
-        if (widget.error != null) ...<Widget>[
-          const SizedBox(height: AppSizes.spaceXs),
-          Text(
-            widget.error!,
-            style: AppTextStyles.emptyMessage.copyWith(
-              color: AppColors.danger,
-            ),
-          ),
-        ],
-      ],
-    );
-  }
-}
-
-/// 一行可点的建议值。
-class _Suggestions extends StatelessWidget {
-  const _Suggestions({
-    required this.label,
-    required this.values,
-    required this.enabled,
-    required this.onPick,
-  });
-
-  final String label;
-  final List<String> values;
-  final bool enabled;
-  final ValueChanged<String> onPick;
-
-  @override
-  Widget build(BuildContext context) {
-    return Row(
-      crossAxisAlignment: CrossAxisAlignment.start,
-      children: <Widget>[
-        Padding(
-          padding: const EdgeInsets.only(top: 5),
-          child: Text(label, style: AppTextStyles.emptyMessage),
-        ),
-        const SizedBox(width: AppSizes.spaceSm),
-        Expanded(
-          child: Wrap(
-            spacing: AppSizes.spaceSm,
-            runSpacing: AppSizes.spaceSm,
-            children: <Widget>[
-              for (final String value in values)
-                _SuggestionChip(
-                  label: value,
-                  onTap: enabled ? () => onPick(value) : null,
-                ),
-            ],
-          ),
-        ),
-      ],
-    );
-  }
-}
-
-class _SuggestionChip extends StatefulWidget {
-  const _SuggestionChip({required this.label, required this.onTap});
-
-  final String label;
-  final VoidCallback? onTap;
-
-  @override
-  State<_SuggestionChip> createState() => _SuggestionChipState();
-}
-
-class _SuggestionChipState extends State<_SuggestionChip> {
-  bool _hovered = false;
-
-  @override
-  Widget build(BuildContext context) {
-    return MouseRegion(
-      cursor: SystemMouseCursors.click,
-      onEnter: (_) => setState(() => _hovered = true),
-      onExit: (_) => setState(() => _hovered = false),
-      child: GestureDetector(
-        onTap: widget.onTap,
-        child: AnimatedContainer(
-          duration: AppSizes.transition,
-          padding: const EdgeInsets.symmetric(horizontal: 10, vertical: 4),
-          decoration: BoxDecoration(
-            color: _hovered ? AppColors.primaryFaint : AppColors.iconSurface,
-            borderRadius: BorderRadius.circular(AppSizes.navItemRadius),
-          ),
-          child: Text(
-            widget.label,
-            style: AppTextStyles.cardDesc.copyWith(
-              color: _hovered ? AppColors.primary : AppColors.textSecondary,
-            ),
-          ),
-        ),
-      ),
-    );
-  }
-}
-
-/// 底部按钮：左「取消」，右「提交」。
-class _Actions extends StatelessWidget {
-  const _Actions({
-    required this.submitting,
-    required this.onCancel,
-    required this.onSubmit,
-  });
-
-  final bool submitting;
-  final VoidCallback onCancel;
-  final VoidCallback onSubmit;
-
-  @override
-  Widget build(BuildContext context) {
-    return Row(
-      mainAxisAlignment: MainAxisAlignment.end,
-      children: <Widget>[
-        DialogGhostButton(label: '取消', onTap: submitting ? null : onCancel),
-        const SizedBox(width: AppSizes.spaceMd),
-        DialogPrimaryButton(
-          label: submitting ? '提交中…' : '提交',
-          onTap: submitting ? null : onSubmit,
-        ),
-      ],
-    );
-  }
-}
-
-class _IconButton extends StatefulWidget {
-  const _IconButton({
-    required this.icon,
-    required this.tooltip,
-    required this.onTap,
-  });
-
-  final String icon;
-  final String tooltip;
-  final VoidCallback? onTap;
-
-  @override
-  State<_IconButton> createState() => _IconButtonState();
-}
-
-class _IconButtonState extends State<_IconButton> {
-  bool _hovered = false;
-
-  @override
-  Widget build(BuildContext context) {
-    return Tooltip(
-      message: widget.tooltip,
-      child: MouseRegion(
-        cursor: SystemMouseCursors.click,
-        onEnter: (_) => setState(() => _hovered = true),
-        onExit: (_) => setState(() => _hovered = false),
-        child: GestureDetector(
-          onTap: widget.onTap,
-          child: AnimatedContainer(
-            duration: AppSizes.transition,
-            width: AppSizes.iconButtonSize,
-            height: AppSizes.iconButtonSize,
-            alignment: Alignment.center,
-            decoration: BoxDecoration(
-              color: _hovered ? AppColors.iconSurface : Colors.transparent,
-              borderRadius: BorderRadius.circular(AppSizes.navItemRadius),
-            ),
-            child: Text(
-              widget.icon,
-              style: AppTextStyles.cardTitle.copyWith(
-                color: AppColors.textSecondary,
-              ),
-            ),
-          ),
-        ),
-      ),
-    );
-  }
-}
-
-// ---- 校验：口径与后端 validate.rs 保持一致 ----
-
-const int _maxTitle = 60;
-const int _maxDescription = 120;
-const int _maxGroup = 30;
-const int _maxSubmittedBy = 120;
-
-String? _validateTitle(String value) {
-  if (value.trim().isEmpty) {
-    return '请填写网站名称';
-  }
-  if (charCount(value) > _maxTitle) {
-    return '网站名称最多 $_maxTitle 个字';
-  }
-  return null;
-}
-
-String? _validateUrl(String value) {
-  final String text = value.trim();
-  if (text.isEmpty) {
-    return '请填写网站地址';
-  }
-  final Uri? uri = Uri.tryParse(text);
-  if (uri == null || uri.host.isEmpty) {
-    return '地址要以 http:// 或 https:// 开头';
-  }
-  if (uri.scheme != 'http' && uri.scheme != 'https') {
-    return '地址只能是 http:// 或 https://';
-  }
-  if (_isInternalHost(uri.host)) {
-    return '不能填本机或内网地址';
-  }
-  return null;
-}
-
-String? _validateDescription(String value) {
-  if (charCount(value) > _maxDescription) {
-    return '描述最多 $_maxDescription 个字';
-  }
-  return null;
-}
-
-String? _validateGroup(String value) {
-  final String text = value.trim();
-  if (text.isEmpty) {
-    return '请填写分组名称';
-  }
-  if (charCount(text) > _maxGroup) {
-    return '分组名称最多 $_maxGroup 个字';
-  }
-  return null;
-}
-
-String? _validateSubGroup(String value) {
-  if (charCount(value) > _maxGroup) {
-    return '子分组名称最多 $_maxGroup 个字';
-  }
-  return null;
-}
-
-String? _validateSubmittedBy(String value) {
-  if (charCount(value) > _maxSubmittedBy) {
-    return '最多 $_maxSubmittedBy 个字';
-  }
-  return null;
-}
-
-/// 前端只拦最明显的几种内网地址，权威判断在后端。
-bool _isInternalHost(String host) {
-  final String h = host.toLowerCase();
-  if (h == 'localhost' || h.endsWith('.localhost') || h.endsWith('.local')) {
-    return true;
-  }
-  if (h == '0.0.0.0' || h == '::1' || h == '[::1]') {
-    return true;
-  }
-  final List<String> parts = h.split('.');
-  if (parts.length != 4) {
-    return false;
-  }
-  final int? first = int.tryParse(parts[0]);
-  final int? second = int.tryParse(parts[1]);
-  if (first == null || second == null) {
-    return false;
-  }
-  if (first == 127 || first == 10) {
-    return true;
-  }
-  if (first == 192 && second == 168) {
-    return true;
-  }
-  if (first == 172 && second >= 16 && second <= 31) {
-    return true;
-  }
-  return first == 169 && second == 254;
-}
diff --git a/frontend/test/features/home/presentation/home_page_test.dart b/frontend/test/features/home/presentation/home_page_test.dart
index 94cad23..f94b9d6 100644
--- a/frontend/test/features/home/presentation/home_page_test.dart
+++ b/frontend/test/features/home/presentation/home_page_test.dart
@@ -8,15 +8,11 @@ import 'package:frontend/features/home/data/home_repository.dart';
 import 'package:frontend/features/home/data/mock_home_data.dart';
 import 'package:frontend/features/home/data/mock_home_repository.dart';
 import 'package:frontend/features/home/domain/models/home_data.dart';
-import 'package:frontend/features/home/domain/models/link_item.dart';
-import 'package:frontend/features/home/domain/models/link_section.dart';
-import 'package:frontend/features/home/domain/models/nav_node.dart';
 import 'package:frontend/features/home/domain/models/submit_site_draft.dart';
 import 'package:frontend/features/home/presentation/pages/home_page.dart';
 import 'package:frontend/features/home/presentation/widgets/link_card.dart';
 import 'package:frontend/features/home/presentation/widgets/link_section_view.dart';
 import 'package:frontend/features/home/presentation/widgets/sidebar_nav.dart';
-import 'package:frontend/features/home/presentation/widgets/site_form_dialog.dart';
 
 import '../../../helpers/fake_url_opener.dart';
 
@@ -382,197 +378,18 @@ void main() {
   });
 
   group('提交网站', () {
-    testWidgets('点侧栏底部按钮打开表单；提交成功后刷新一次并提示', (WidgetTester tester) async {
-      final _RecordingRepository repository = _RecordingRepository();
-      // 表单比默认视口高，用大一点的窗口，免得字段在屏幕外点不到。
-      await pumpPage(
-        tester,
-        size: const Size(1000, 1200),
-        repository: repository,
-      );
-      expect(repository.fetches, 1);
-
-      await tester.tap(navText('提交网站'));
-      await tester.pumpAndSettle();
-      expect(find.text('网站名称'), findsOneWidget);
-      expect(find.text('提交的网站会放在你自己的分组里，不会进内置分类。'), findsOneWidget);
-
-      // 页面里除了表单还有顶部搜索框，这里限定在对话框内部找输入框。
-      Finder field(int index) => find
-          .descendant(
-            of: find.byType(SiteFormDialog),
-            matching: find.byType(TextField),
-          )
-          .at(index);
-
-      await tester.enterText(field(0), 'Hugging Face');
-      await tester.enterText(field(1), 'https://huggingface.co');
-      await tester.enterText(field(3), 'AI 工具');
-      await tester.pump();
-
-      await tester.tap(find.text('提交'));
-      await tester.pumpAndSettle();
-
-      expect(repository.submitted, hasLength(1));
-      expect(repository.submitted.single.group, 'AI 工具');
-      expect(repository.fetches, 2, reason: '提交成功后要重新拉一次数据');
-      expect(find.text('已提交，感谢'), findsOneWidget);
-      expect(find.text('网站名称'), findsNothing, reason: '对话框已经关掉');
-    });
-  });
-
-  group('编辑与删除', () {
-    testWidgets('可修改的条目能编辑，保存后刷新', (WidgetTester tester) async {
-      final _MutableRepository repository = _MutableRepository();
-      await pumpPage(
-        tester,
-        size: const Size(1000, 1200),
-        repository: repository,
-      );
-      expect(repository.fetches, 1);
-
-      await tester.tap(find.byTooltip('编辑'));
-      await tester.pumpAndSettle();
-
-      // 表单预填了现有内容，提交者字段不出现。
-      expect(find.text('编辑网站'), findsOneWidget);
-      expect(
-        tester
-            .widget<TextField>(
-              find
-                  .descendant(
-                    of: find.byType(SiteFormDialog),
-                    matching: find.byType(TextField),
-                  )
-                  .at(0),
-            )
-            .controller!
-            .text,
-        'Hugging Face',
-      );
-
-      await tester.tap(find.text('提交'));
-      await tester.pumpAndSettle();
-
-      expect(repository.updated, <String>['s-1']);
-      expect(repository.fetches, 2, reason: '保存成功后要重新拉一次数据');
-      expect(find.text('已保存'), findsOneWidget);
-    });
-
-    testWidgets('删除会先确认，确认后才真的删并刷新', (WidgetTester tester) async {
-      final _MutableRepository repository = _MutableRepository();
-      await pumpPage(
-        tester,
-        size: const Size(1000, 1200),
-        repository: repository,
-      );
-
-      await tester.tap(find.byTooltip('删除'));
-      await tester.pumpAndSettle();
-      expect(find.textContaining('确定要删除「Hugging Face」'), findsOneWidget);
-
-      // 先点取消：什么都不该发生。
-      await tester.tap(find.text('取消'));
-      await tester.pumpAndSettle();
-      expect(repository.deleted, isEmpty);
-
-      await tester.tap(find.byTooltip('删除'));
-      await tester.pumpAndSettle();
-      await tester.tap(find.text('删除'));
-      await tester.pumpAndSettle();
-
-      expect(repository.deleted, <String>['s-1']);
-      expect(repository.fetches, 2);
-      expect(find.text('已删除'), findsOneWidget);
-    });
-
-    testWidgets('内置条目没有编辑和删除入口', (WidgetTester tester) async {
+    testWidgets('点侧栏底部按钮跳到后端配的提交入口', (WidgetTester tester) async {
       await pumpPage(tester);
 
-      expect(find.byType(LinkCard), findsWidgets);
-      expect(find.byTooltip('编辑'), findsNothing);
-      expect(find.byTooltip('删除'), findsNothing);
+      await tester.tap(navText('提交网站'));
+      await tester.pump();
+
+      // 地址来自后端 `site.submitUrl`，页面不再自己弹表单。
+      expect(urlOpener.openedUrls, <String>['https://mattermost.example.com']);
     });
   });
 }
 
-/// 返回一条「用户提交」的站点（editable），并记录改删调用。
-class _MutableRepository implements HomeRepository {
-  int fetches = 0;
-  final List<String> updated = <String>[];
-  final List<String> deleted = <String>[];
-
-  static const HomeData _data = HomeData(
-    siteName: 'Suxing Nav',
-    searchHint: '输入关键字搜索全网资源...',
-    navNodes: <NavNode>[NavNode(id: 'g-1', title: 'AI 工具', editable: true)],
-    sections: <LinkSection>[
-      LinkSection(
-        id: 'g-1',
-        title: 'AI 工具',
-        items: <LinkItem>[
-          LinkItem(
-            id: 's-1',
-            title: 'Hugging Face',
-            url: 'https://huggingface.co',
-            description: '开源模型与数据集社区',
-            categoryId: 'g-1',
-            editable: true,
-          ),
-        ],
-      ),
-    ],
-  );
-
-  @override
-  Future<HomeData> fetchHomeData() async {
-    fetches++;
-    return _data;
-  }
-
-  @override
-  Future<void> submitSite(SubmitSiteDraft draft) async {}
-
-  @override
-  Future<void> updateSite(String id, SubmitSiteDraft draft) async {
-    updated.add(id);
-  }
-
-  @override
-  Future<void> deleteSite(String id) async {
-    deleted.add(id);
-  }
-}
-
-/// 记录取数次数与提交内容，用来验证页面的联调行为。
-class _RecordingRepository implements HomeRepository {
-  int fetches = 0;
-  final List<SubmitSiteDraft> submitted = <SubmitSiteDraft>[];
-  final List<String> updated = <String>[];
-  final List<String> deleted = <String>[];
-
-  @override
-  Future<HomeData> fetchHomeData() async {
-    fetches++;
-    return mockHomeData;
-  }
-
-  @override
-  Future<void> submitSite(SubmitSiteDraft draft) async {
-    submitted.add(draft);
-  }
-
-  @override
-  Future<void> updateSite(String id, SubmitSiteDraft draft) async {
-    updated.add(id);
-  }
-
-  @override
-  Future<void> deleteSite(String id) async {
-    deleted.add(id);
-  }
-}
-
 /// 数据一直不回来，用来测加载中的那一帧。
 class _PendingRepository implements HomeRepository {
   final Completer<HomeData> completer = Completer<HomeData>();
diff --git a/frontend/test/features/home/presentation/site_form_dialog_test.dart b/frontend/test/features/home/presentation/site_form_dialog_test.dart
deleted file mode 100644
index 5c33a66..0000000
--- a/frontend/test/features/home/presentation/site_form_dialog_test.dart
+++ /dev/null
@@ -1,235 +0,0 @@
-import 'dart:async';
-
-import 'package:flutter/material.dart';
-import 'package:flutter_test/flutter_test.dart';
-import 'package:frontend/features/home/data/home_repository.dart';
-import 'package:frontend/features/home/data/mock_home_data.dart';
-import 'package:frontend/features/home/domain/models/home_data.dart';
-import 'package:frontend/features/home/domain/models/nav_node.dart';
-import 'package:frontend/features/home/domain/models/submit_site_draft.dart';
-import 'package:frontend/features/home/presentation/widgets/site_form_dialog.dart';
-
-/// 记录提交内容的假仓库。[failWith] 有值时模拟后端报错，[gate] 用来卡住请求。
-class _RecordingRepository implements HomeRepository {
-  final List<SubmitSiteDraft> submitted = <SubmitSiteDraft>[];
-  String? failWith;
-  Completer<void>? gate;
-
-  @override
-  Future<HomeData> fetchHomeData() async => mockHomeData;
-
-  @override
-  Future<void> submitSite(SubmitSiteDraft draft) async {
-    if (gate != null) {
-      await gate!.future;
-    }
-    final String? failure = failWith;
-    if (failure != null) {
-      throw HomeFailure(failure);
-    }
-    submitted.add(draft);
-  }
-
-  @override
-  Future<void> updateSite(String id, SubmitSiteDraft draft) async {}
-
-  @override
-  Future<void> deleteSite(String id) async {}
-}
-
-/// 侧栏那棵树：内置分组不可选，用户分组可选。
-const List<NavNode> _navNodes = <NavNode>[
-  NavNode(id: 'common', title: '常用推荐'),
-  NavNode(
-    id: 'g-1',
-    title: 'AI 工具',
-    editable: true,
-    children: <NavNode>[
-      NavNode(id: 'g-2', title: '模型社区', editable: true),
-    ],
-  ),
-];
-
-void main() {
-  late _RecordingRepository repository;
-  late bool? dialogResult;
-
-  setUp(() {
-    repository = _RecordingRepository();
-    dialogResult = null;
-  });
-
-  Future<void> openDialog(
-    WidgetTester tester, {
-    String heading = '提交网站',
-    SubmitSiteDraft? initial,
-  }) async {
-    // 表单比默认测试视口高，放大一点免得字段跑到屏幕外。
-    tester.view.physicalSize = const Size(1000, 1200);
-    tester.view.devicePixelRatio = 1;
-    addTearDown(tester.view.reset);
-
-    await tester.pumpWidget(
-      MaterialApp(
-        home: Scaffold(
-          body: Builder(
-            builder: (BuildContext context) => TextButton(
-              onPressed: () async {
-                dialogResult = await showSiteFormDialog(
-                  context: context,
-                  navNodes: _navNodes,
-                  heading: heading,
-                  initial: initial,
-                  onSubmit: (SubmitSiteDraft draft) =>
-                      repository.submitSite(draft),
-                );
-              },
-              child: const Text('打开'),
-            ),
-          ),
-        ),
-      ),
-    );
-    await tester.tap(find.text('打开'));
-    await tester.pumpAndSettle();
-  }
-
-  /// 按顺序填字段：0 名称、1 地址、2 描述、3 分组、4 子分组、5 称呼。
-  Future<void> fill(WidgetTester tester, int index, String value) async {
-    await tester.enterText(find.byType(TextField).at(index), value);
-    await tester.pump();
-  }
-
-  Future<void> fillValidForm(WidgetTester tester) async {
-    await fill(tester, 0, 'Hugging Face');
-    await fill(tester, 1, 'https://huggingface.co');
-    await fill(tester, 2, '开源模型与数据集社区');
-    await fill(tester, 3, 'AI 工具');
-    await fill(tester, 4, '模型社区');
-    await fill(tester, 5, 'an@example.com');
-  }
-
-  testWidgets('空表单提交会逐项提示，且不发请求', (WidgetTester tester) async {
-    await openDialog(tester);
-
-    await tester.tap(find.text('提交'));
-    await tester.pumpAndSettle();
-
-    expect(find.text('请填写网站名称'), findsOneWidget);
-    expect(find.text('请填写网站地址'), findsOneWidget);
-    expect(find.text('请填写分组名称'), findsOneWidget);
-    expect(repository.submitted, isEmpty);
-    expect(dialogResult, isNull, reason: '校验没过时对话框不关');
-  });
-
-  testWidgets('内网地址会被拦下来', (WidgetTester tester) async {
-    await openDialog(tester);
-    await fill(tester, 0, '内网');
-    await fill(tester, 1, 'http://192.168.1.10');
-    await fill(tester, 3, 'AI 工具');
-
-    await tester.tap(find.text('提交'));
-    await tester.pumpAndSettle();
-
-    expect(find.text('不能填本机或内网地址'), findsOneWidget);
-    expect(repository.submitted, isEmpty);
-  });
-
-  testWidgets('合法内容提交给仓库，成功后关闭并返回 true', (WidgetTester tester) async {
-    await openDialog(tester);
-    await fillValidForm(tester);
-
-    await tester.tap(find.text('提交'));
-    await tester.pumpAndSettle();
-
-    expect(repository.submitted, hasLength(1));
-    final SubmitSiteDraft draft = repository.submitted.single;
-    expect(draft.title, 'Hugging Face');
-    expect(draft.url, 'https://huggingface.co');
-    expect(draft.group, 'AI 工具');
-    expect(draft.subGroup, '模型社区');
-    expect(draft.submittedBy, 'an@example.com');
-    expect(dialogResult, isTrue);
-    expect(find.text('取消'), findsNothing, reason: '对话框已经关掉');
-  });
-
-  testWidgets('后端报错时留在表单里显示原因', (WidgetTester tester) async {
-    repository.failWith = 'url 不能是本机或内网地址：localhost';
-    await openDialog(tester);
-    await fillValidForm(tester);
-
-    await tester.tap(find.text('提交'));
-    await tester.pumpAndSettle();
-
-    expect(find.textContaining('不能是本机或内网地址'), findsOneWidget);
-    expect(repository.submitted, isEmpty);
-    expect(dialogResult, isNull);
-    expect(find.text('取消'), findsOneWidget, reason: '还能改了再提交');
-  });
-
-  testWidgets('提交中按钮变成「提交中…」且不可再点', (WidgetTester tester) async {
-    repository.gate = Completer<void>();
-    await openDialog(tester);
-    await fillValidForm(tester);
-
-    await tester.tap(find.text('提交'));
-    await tester.pump();
-
-    expect(find.text('提交中…'), findsOneWidget);
-
-    repository.gate!.complete();
-    await tester.pumpAndSettle();
-    expect(dialogResult, isTrue);
-  });
-
-  testWidgets('只给用户分组建议，点一下填进输入框', (WidgetTester tester) async {
-    await openDialog(tester);
-
-    // 内置分组不出现在建议里。
-    expect(find.text('AI 工具'), findsOneWidget, reason: '用户分组建议');
-    expect(find.text('常用推荐'), findsNothing, reason: '内置分组不可选');
-
-    await tester.tap(find.text('AI 工具'));
-    await tester.pumpAndSettle();
-
-    final TextField groupField = tester.widget<TextField>(
-      find.byType(TextField).at(3),
-    );
-    expect(groupField.controller!.text, 'AI 工具');
-    // 分组定了之后，它下面已有的子分组才出现。
-    expect(find.text('模型社区'), findsOneWidget);
-  });
-
-  testWidgets('编辑模式预填现有内容，且不显示提交者字段', (WidgetTester tester) async {
-    await openDialog(
-      tester,
-      heading: '编辑网站',
-      initial: const SubmitSiteDraft(
-        title: 'Hugging Face',
-        url: 'https://huggingface.co',
-        description: '开源模型与数据集社区',
-        group: 'AI 工具',
-        subGroup: '模型社区',
-      ),
-    );
-
-    expect(find.text('编辑网站'), findsOneWidget);
-    expect(
-      tester.widget<TextField>(find.byType(TextField).at(0)).controller!.text,
-      'Hugging Face',
-    );
-    expect(
-      tester.widget<TextField>(find.byType(TextField).at(1)).controller!.text,
-      'https://huggingface.co',
-    );
-    expect(
-      tester.widget<TextField>(find.byType(TextField).at(3)).controller!.text,
-      'AI 工具',
-    );
-    // 后端 PATCH 不接受 submittedBy，编辑时就不显示这个字段。
-    expect(find.text('你的称呼或邮箱'), findsNothing);
-    // 分组已填好，它下面的子分组建议直接出来。
-    // （子分组输入框里也预填了同样的文字，所以这里用 findsWidgets。）
-    expect(find.text('模型社区'), findsWidgets);
-  });
-}