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]>
