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/routes/console/library.$id.tsx

@@ -482,7 +482,7 @@ function DownloadsPanel({ detail }: { detail: LibraryDetail }) {
       cell: (d) => (
         <div className="min-w-0">
           <Link
-            to={consolePath("tasks", d.downloadTask.id)}
+            to={consolePath("downloads", d.downloadTask.id)}
             className="block max-w-[14rem] truncate font-mono text-caption text-foreground hover:underline sm:max-w-md"
             title={d.downloadTask.name}
           >