feat(content): 分组对所有内容类型生效，统一分区/分组/条目模型

- 分区=容器，分组=任意类型的可选子容器，条目可挂分区或分组（直属分区）
- catalog 所有类型统一输出 groups + items，条目查询按节点取
- 详情/侧栏/首页卡片预览支持所有类型的分组；多组显示小标题 + 未分组
- 后台「分区」「侧栏导航」对所有类型可建组；「内容」弹窗分组可选直属分区，编辑可换组
- 修复首页卡片配置为「整个分区」时预览为空
- 测试 59 passed

stash-web/src/components/content/HomeView.tsx

@@ -57,7 +57,7 @@ export function HomeView({ categories, sections, onOpenDetail, onOpenItem }: Hom
  * 否则（电影 / 文章 / 本地服务）数整个分区。
  */
 function cardCount(category: Category): number {
-  if (category.kind === 'apps' && category.block !== undefined) {
+  if (category.block !== undefined) {
     const group = category.groups.find((item) => item.id === category.block?.nodeKey)
     if (group !== undefined) return group.items.length
   }
@@ -65,6 +65,12 @@ function cardCount(category: Category): number {
   return categoryCount(category)
 }
 
+/** 某个分区配的「首页预览分组」；没配或找不到返回 undefined */
+function blockGroup<T>(category: { block?: { nodeKey?: string }; groups: { id: string; items: T[] }[] }) {
+  if (category.block?.nodeKey === undefined) return undefined
+  return category.groups.find((group) => group.id === category.block?.nodeKey)
+}
+
 /** 按分类类型输出对应的预览网格；应用类为空时给出提示文案 */
 function renderPreview(
   category: Category,
@@ -72,13 +78,9 @@ function renderPreview(
   onOpenItem: (categoryId: string, itemId: string) => void,
 ) {
   if (category.kind === 'apps') {
-    // 配了展示块就只展示那个分组；没有配置（如「本地服务」）则退回全部条目
-    const blockGroup =
-      category.block !== undefined
-        ? category.groups.find((group) => group.id === category.block?.nodeKey)
-        : undefined
-
-    const source = category.block !== undefined ? (blockGroup?.items ?? []) : flattenAppItems(category)
+    // 配了展示块且指向分组时只展示该组；展示块指向分区本身（「整个分区」）时展示全部条目
+    const group = blockGroup(category)
+    const source = group !== undefined ? group.items : flattenAppItems(category)
     const fallback = category.block?.previewLimit ?? category.previewLimit ?? 4
     const limit = sectionLimit(category.id, fallback, sections)
     const items = source.slice(0, limit)
@@ -91,17 +93,25 @@ function renderPreview(
   }
 
   if (category.kind === 'posters') {
+    const group = blockGroup(category)
+    const source = group
+      ? group.items
+      : [...category.items, ...category.groups.flatMap((item) => item.items)]
     return (
       <PosterGrid
-        items={category.items.slice(0, sectionLimit(category.id, category.previewLimit ?? 6, sections))}
+        items={source.slice(0, sectionLimit(category.id, category.previewLimit ?? 6, sections))}
         onOpen={(itemId) => onOpenItem(category.id, itemId)}
       />
     )
   }
 
+  const group = blockGroup(category)
+  const source = group
+    ? group.items
+    : [...category.items, ...category.groups.flatMap((item) => item.items)]
   return (
     <ArticleGrid
-      items={category.items.slice(0, sectionLimit(category.id, category.previewLimit ?? 4, sections))}
+      items={source.slice(0, sectionLimit(category.id, category.previewLimit ?? 4, sections))}
       onOpen={(itemId) => onOpenItem(category.id, itemId)}
     />
   )