feat(web): regroup console nav into 7 groups, split downloads/plans/tasks, add legacy redirects

- Sidebar: 概览/资源/订阅/下载/整理/Agent/系统, 18 items (+ 定时任务); single
  active item via findNavItem; 待处理 badge; collapsed rail groups; mobile drawer
  shares NAV_GROUPS.
- New pages: /downloads (queue + cache watermark header), /downloads/plans,
  /downloads/:id, /tasks (business tasks only) + /tasks/:id detail, /rules.
- Legacy links: ?tab= on tasks/subscriptions/sources redirect via clientLoader;
  /tasks/:downloadId falls back to /downloads/:id.
- List filters in URL query; settingsPath() helper for settings deep links.
- Copy per glossary (待处理, 收录策略, 引擎面板, 文件管理, 版本目标).

Co-Authored-By: Claude Opus 5.5 <[email protected]>

apps/web/app/components/library/subscriptions-policy.tsx

@@ -208,7 +208,6 @@ export function PolicyWorkspace({
 
   return (
     <div className="space-y-4">
-      <p className="text-caption text-muted-foreground">草案发布后才生效。回滚会用旧版本内容发布一个新版本。</p>
       {q.isPending ? (
         <div className="pg-slab rounded-xl p-4">
           <LoadingState rows={4} />