feat: 格式从分组下沉到条目（v21）

- entry 新增 format（apps/posters/articles），老数据按根分组 view_mode 回填；seed 按分区写入
- 分组管理移除格式字段/显示，根分组只作容器
- 内容弹窗新增逐条格式选择，列表增加格式列；ItemEditor 保存时保留原格式
- 前台按 entry.format 渲染：卡片/分组页支持同组混合格式，详情按条目格式选模板
- 迁移后 live 20 应用 / 13 海报；cargo test 59 passed；Playwright 验证混合展示

stash-web/src/AppNext.tsx

@@ -144,8 +144,12 @@ function collectEntries(group: GroupNode): Record<string, unknown>[] {
 }
 
 function defaultLimit(group: GroupNode): number {
-  const fallback = group.format === 'apps' ? 4 : group.format === 'posters' ? 6 : 4
-  return group.previewLimit ?? fallback
+  return group.previewLimit ?? 6
+}
+
+function entryFormat(entry: Record<string, unknown>): 'apps' | 'posters' | 'articles' {
+  const value = entry.format
+  return value === 'posters' || value === 'articles' ? value : 'apps'
 }
 
 function matches(entry: Record<string, unknown>, keyword: string): boolean {
@@ -273,13 +277,25 @@ export default function AppNext() {
     const items = filtered.slice(0, limit)
     const open = (itemId: string) => navigate(`/g/${encodeURIComponent(group.key)}/i/${encodeURIComponent(itemId)}`)
 
-    if (group.format === 'posters') {
-      return <PosterGrid items={items as unknown as PosterItem[]} onOpen={open} />
-    }
-    if (group.format === 'articles') {
-      return <CesCardGrid items={items as unknown as ArticleItem[]} onOpen={open} />
-    }
-    return <AppGrid items={items as unknown as AppItem[]} onOpen={open} />
+    return (
+      <>
+        {(['apps', 'posters', 'articles'] as const).map((format) => {
+          const subset = items.filter((entry) => entryFormat(entry) === format)
+          if (subset.length === 0) return null
+          return (
+            <div className="mixed-format-block" key={format}>
+              {format === 'posters' ? (
+                <PosterGrid items={subset as unknown as PosterItem[]} onOpen={open} />
+              ) : format === 'articles' ? (
+                <CesCardGrid items={subset as unknown as ArticleItem[]} onOpen={open} />
+              ) : (
+                <AppGrid items={subset as unknown as AppItem[]} onOpen={open} />
+              )}
+            </div>
+          )
+        })}
+      </>
+    )
   }
 
   function renderGroupBlock(group: GroupNode, limit: number, showTitle: boolean) {
@@ -423,7 +439,9 @@ export default function AppNext() {
       { label: String(entry.name ?? entry.title ?? entry.id) },
     ]
 
-    if (group.format === 'articles') {
+    const format = entryFormat(entry)
+
+    if (format === 'articles') {
       const article = entry as unknown as ArticleItem
       return (
         <ArticleDetailView
@@ -438,18 +456,18 @@ export default function AppNext() {
     }
 
     const model: ItemDetailModel =
-      group.format === 'posters'
+      format === 'posters'
         ? posterDetailModel(entry as unknown as PosterItem)
         : appDetailModel(entry as unknown as AppItem)
 
     const related: RelatedItem[] =
-      group.format === 'posters'
+      format === 'posters'
         ? group.entries
-            .filter((item) => item.id !== entry.id)
+            .filter((item) => item.id !== entry.id && entryFormat(item as unknown as Record<string, unknown>) === format)
             .slice(0, 4)
             .map((item) => posterToRelatedItem(item as unknown as PosterItem))
         : group.entries
-            .filter((item) => item.id !== entry.id)
+            .filter((item) => item.id !== entry.id && entryFormat(item as unknown as Record<string, unknown>) === format)
             .slice(0, 4)
             .map((item) => toRelatedItem(item as unknown as AppItem))