feat(downloads): fold download plans into download panel (DL-3)

- Waiting plans (approval / disk space / automation off / queued) are
  active-segment rows on /download-tasks/board, merged by created_at,
  counted, with approve / cancel actions; ?plan= deep links and legacy
  /downloads/plans routes redirect to the panel
- Download detail shows "why this download" (source, purpose, replaced
  version, reasons); raw evaluation in tech info
- Failed / cancelled / expired plans appear in the entity download
  history; rejected / revoked / expired approvals close draft plans
- New GET /acquisition-plans/{id}/why, POST /acquisition-plans/{id}/cancel
- User-facing copy no longer says 下载计划; glossary updated

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

apps/server/src/modules/search/actions.ts

@@ -30,7 +30,6 @@ export const SEARCH_ACTIONS: readonly SearchAction[] = [
   page("subscriptions", "订阅", "订阅", "/console/subscriptions", ["subscription", "追剧"]),
   page("rules", "订阅", "规则", "/console/rules", ["rules", "收录策略", "policy"]),
   page("downloads", "整理", "下载面板", "/console/downloads", ["download", "qb", "下载任务"]),
-  page("download-plans", "整理", "下载计划", "/console/downloads/plans", ["plan", "计划"]),
   page("organize", "整理", "整理记录", "/console/organize", ["organize", "入库", "历史"]),
   page("files", "整理", "文件管理", "/console/files", ["files", "文件"]),
   page("trash", "整理", "回收站", "/console/files/trash", ["trash", "删除"]),