feat(admin): 首页卡片配置 + 页头开关验证 + 编辑按钮仅登录可见

- settings.sections：显隐 / 顺序 / 标题覆盖 / 预览条数，HomeView 应用
- /admin 新增「首页卡片」Tab，卡片标题使用展示块标题（常用站点等）
- 详情页 [编辑] 仅在登录后渲染（canEdit）
- 测试：46 passed；页头禁用、卡片隐藏/改标题/限条数、编辑可见性均实测
- 文档：ADMIN-PLAN、README

stash-web/src/components/admin/AdminPage.tsx

@@ -20,6 +20,7 @@ import {
   saveSettings,
   TONE_OPTIONS,
   type HeaderItem,
+  type SectionSettings,
   type SettingsDocument,
   type SettingsTone,
   type SiteSettings,
@@ -31,7 +32,12 @@ import {
  * 只做「全局配置」；条目内容仍在详情页就地编辑（P2）。
  * 保存用 `version` 乐观锁，冲突时提示刷新。
  */
-type CategorySummary = { id: string; title: string }
+type CategorySummary = {
+  id: string
+  title: string
+  /** 首页卡片标题（配了展示块时用块的标题，如「常用站点」） */
+  block?: { title?: string } | null
+}
 
 const clone = (settings: SiteSettings): SiteSettings => structuredClone(settings)
 
@@ -137,6 +143,7 @@ export function AdminPage() {
               <Tabs
                 items={[
                   { key: 'header', label: '页头滚动信息' },
+                  { key: 'sections', label: '首页卡片' },
                   { key: 'sidebar', label: '侧栏导航' },
                   { key: 'system', label: '系统' },
                 ]}
@@ -155,6 +162,12 @@ export function AdminPage() {
                   value={draft.header}
                   onChange={(header) => setDraft({ ...draft, header })}
                 />
+              ) : tab === 'sections' ? (
+                <SectionForm
+                  categories={categories}
+                  value={draft.sections}
+                  onChange={(sections) => setDraft({ ...draft, sections })}
+                />
               ) : tab === 'sidebar' ? (
                 <SidebarForm
                   categories={categories}
@@ -365,6 +378,108 @@ function SidebarForm({
   )
 }
 
+// ---------- 首页卡片表单 ----------
+
+function SectionForm({
+  categories,
+  value,
+  onChange,
+}: {
+  categories: CategorySummary[]
+  value: SectionSettings
+  onChange: (sections: SectionSettings) => void
+}) {
+  const cards = useMemo(() => {
+    const base = [
+      { id: 'local', title: '本地服务' },
+      ...categories
+        .filter((category) => category.id !== 'local')
+        .map((category) => ({
+          id: category.id,
+          title: category.block?.title ?? category.title,
+        })),
+    ]
+    const ranks = new Map(value.order.map((id, index) => [id, index]))
+
+    return [...base].sort((a, b) => {
+      const left = ranks.get(a.id) ?? Number.MAX_SAFE_INTEGER
+      const right = ranks.get(b.id) ?? Number.MAX_SAFE_INTEGER
+      return left - right
+    })
+  }, [categories, value.order])
+
+  const setOrder = (ids: string[]) => onChange({ ...value, order: ids })
+
+  const move = (index: number, step: -1 | 1) => {
+    const target = index + step
+    if (target < 0 || target >= cards.length) return
+    const ids = cards.map((card) => card.id)
+    const [id] = ids.splice(index, 1)
+    ids.splice(target, 0, id)
+    setOrder(ids)
+  }
+
+  const toggle = (id: string, visible: boolean) => {
+    const hidden = visible
+      ? value.hidden.filter((entry) => entry !== id)
+      : [...new Set([...value.hidden, id])]
+    onChange({ ...value, hidden, order: cards.map((card) => card.id) })
+  }
+
+  const setTitle = (id: string, title: string) => {
+    const titles = { ...value.titles }
+    if (title.trim() === '') delete titles[id]
+    else titles[id] = title
+    onChange({ ...value, titles })
+  }
+
+  const setLimit = (id: string, raw: string) => {
+    const limits = { ...value.limits }
+    const limit = Number(raw)
+    if (raw.trim() === '' || !Number.isFinite(limit) || limit <= 0) delete limits[id]
+    else limits[id] = Math.min(60, Math.round(limit))
+    onChange({ ...value, limits })
+  }
+
+  return (
+    <Space direction="column" gap="sm" align="stretch" className="admin-form">
+      <Text size="sm" tone="muted">
+        控制首页卡片：显示 / 隐藏、标题、每张卡预览条数与顺序。留空表示用内容库里的默认值。
+      </Text>
+
+      {cards.map((card, index) => (
+        <div className="admin-item-row admin-section-row" key={card.id}>
+          <Switch
+            checked={!value.hidden.includes(card.id)}
+            onChange={(next) => toggle(card.id, next)}
+            label={`显示 ${card.title}`}
+          />
+          <Input
+            value={value.titles[card.id] ?? ''}
+            placeholder={card.title}
+            aria-label={`${card.title} 标题`}
+            onChange={(event) => setTitle(card.id, event.target.value)}
+          />
+          <Input
+            type="number"
+            value={value.limits[card.id] === undefined ? '' : String(value.limits[card.id])}
+            placeholder="条数"
+            aria-label={`${card.title} 预览条数`}
+            onChange={(event) => setLimit(card.id, event.target.value)}
+          />
+          <IconButtonGroup
+            onUp={() => move(index, -1)}
+            onDown={() => move(index, 1)}
+            onRemove={undefined}
+          />
+        </div>
+      ))}
+
+      {cards.length === 0 && <Text tone="muted">内容库还没有加载完成。</Text>}
+    </Space>
+  )
+}
+
 // ---------- 系统 ----------
 
 function SystemPanel() {