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/web/app/routes.ts

@@ -27,6 +27,7 @@ export default [
       route("rules", "routes/console/rules.tsx"),
       route("downloads", "routes/console/downloads.tsx"),
       route("downloads/plans", "routes/console/downloads.plans.tsx"),
+      route("downloads/plans/:id", "routes/console/downloads.plans.tsx", { id: "downloads-plan-legacy" }),
       route("downloads/:id", "routes/console/downloads.$id.tsx"),
       route("tasks", "routes/console/tasks.tsx"),
       route("tasks/:id", "routes/console/tasks.$id.tsx"),