feat(admin): 完善站点设置、内容回收站与后台菜单分组

新增站点设置与内容管理（含已删除恢复/清除），用户页改用独有运营指标，并按概览/内容/成员与经济/站点重组侧栏。

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/app/admin/announcements/AnnouncementAdmin.tsx

@@ -11,7 +11,6 @@ import {
   X,
   ExternalLink,
   Megaphone,
-  FileText,
 } from "lucide-react";
 import {
   apiAdminListAnnouncements,
@@ -24,6 +23,7 @@ import {
 } from "@/lib/api";
 import { formatDate } from "@/lib/format";
 import { toast } from "@/lib/toast";
+import ConfirmDialog from "@/components/ConfirmDialog";
 
 const COLORS: { value: AnnouncementColor; label: string }[] = [
   { value: "blue", label: "蓝色" },
@@ -52,6 +52,7 @@ export default function AnnouncementAdmin() {
   const [form, setForm] = useState<FormState | null>(null);
   const [saving, setSaving] = useState(false);
   const [deletingId, setDeletingId] = useState<number | null>(null);
+  const [deleteTarget, setDeleteTarget] = useState<Announcement | null>(null);
 
   const load = useCallback(async () => {
     setLoading(true);
@@ -113,7 +114,6 @@ export default function AnnouncementAdmin() {
   }
 
   async function remove(a: Announcement) {
-    if (!window.confirm(`确定删除公告「${a.title}」吗？此操作不可撤销。`)) return;
     setDeletingId(a.id);
     try {
       await apiAdminDeleteAnnouncement(a.id);
@@ -124,6 +124,7 @@ export default function AnnouncementAdmin() {
       toast(e instanceof Error ? e.message : "删除失败");
     } finally {
       setDeletingId(null);
+      setDeleteTarget(null);
     }
   }
 
@@ -150,10 +151,10 @@ export default function AnnouncementAdmin() {
         )}
       </div>
 
-      <div className="grid grid-cols-1 lg:grid-cols-[400px_minmax(0,1fr)] gap-6 items-start">
-        {/* 编辑/新建表单 */}
-        {form ? (
-          <div className="panel p-5 lg:sticky lg:top-24">
+      <div className="grid grid-cols-1 gap-6 items-start">
+        {/* 编辑/新建表单：仅在新建或编辑时展开，空闲不占位 */}
+        {form && (
+          <div className="panel p-5">
             <p className="font-semibold text-[15px] mb-4" style={{ color: "var(--ink)" }}>
               {form.id == null ? "新建公告" : "编辑公告"}
             </p>
@@ -257,26 +258,6 @@ export default function AnnouncementAdmin() {
               </button>
             </div>
           </div>
-        ) : (
-          <div className="panel p-6 text-center lg:sticky lg:top-24">
-            <span
-              className="inline-flex w-12 h-12 rounded-2xl items-center justify-center mb-3"
-              style={{ background: "var(--accent-soft)", color: "var(--accent)" }}
-            >
-              <FileText size={22} />
-            </span>
-            <p className="text-[14.5px]" style={{ color: "var(--ink)" }}>
-              公告编辑器
-            </p>
-            <p className="meta mt-1.5 text-[12.5px] leading-relaxed">
-              点击右上「新建公告」发布公告，
-              <br />
-              或在右侧列表中选择已有公告进行编辑。
-            </p>
-            <button onClick={startCreate} className="btn btn-primary mt-4">
-              <Plus size={15} /> 新建公告
-            </button>
-          </div>
         )}
 
         {/* 公告列表 */}
@@ -350,7 +331,7 @@ export default function AnnouncementAdmin() {
                     <Pencil size={15} />
                   </button>
                   <button
-                    onClick={() => remove(a)}
+                    onClick={() => setDeleteTarget(a)}
                     disabled={deletingId === a.id}
                     className="w-8 h-8 inline-flex items-center justify-center rounded-full transition-colors hover:bg-[var(--danger-soft)] disabled:opacity-50"
                     style={{ color: "var(--ink-3)" }}
@@ -367,6 +348,19 @@ export default function AnnouncementAdmin() {
           )}
         </div>
       </div>
+
+      <ConfirmDialog
+        open={!!deleteTarget}
+        title="删除公告"
+        message={deleteTarget ? `确定删除公告「${deleteTarget.title}」吗？此操作不可撤销。` : ""}
+        danger
+        busy={deletingId != null}
+        confirmLabel="删除"
+        onCancel={() => deletingId == null && setDeleteTarget(null)}
+        onConfirm={() => {
+          if (deleteTarget) void remove(deleteTarget);
+        }}
+      />
     </div>
   );
 }