feat: 实现导航页基础功能

- 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/data/site.json

@@ -0,0 +1,4 @@
+{
+  "name": "Suxing Nav",
+  "searchHint": "输入关键字搜索全网资源..."
+}

backend/data/system-categories.json

@@ -0,0 +1,74 @@
+[
+  {
+    "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"
+  }
+]

backend/data/system-sites.json

@@ -0,0 +1,62 @@
+[
+  {
+    "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": ""
+  }
+]

backend/data/user-categories.json

@@ -0,0 +1,47 @@
+[
+  {
+    "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"
+  }
+]

backend/data/user-sites.json

@@ -0,0 +1,14 @@
+[
+  {
+    "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": "[email protected]"
+  }
+]