feat(web): IA-3 navigation, legacy redirects and top-bar inbox (FE-1)

Sidebar becomes 5 groups (overview / resources / subscriptions / organize /
system). Pending items move to a top-bar inbox with badge and grouped
dropdown. Engine panel, schedules and identity pages redirect to the task
page, its plan tab and media overview views; the download plan becomes a
second tab of the download panel. nav.test and smoke cover the new routes.

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

apps/web/app/routes/console/downloads.tsx

@@ -18,12 +18,13 @@ import {
   PauseResume,
   ProgressLine,
 } from "~/components/downloads/download-detail.tsx";
+import { DownloadsTabs } from "~/components/downloads/downloads-tabs.tsx";
 import { Button } from "~/components/ui/button.tsx";
 import { relTime } from "~/components/workbench/release-fields.ts";
 import { useSse } from "~/lib/sse.ts";
 import { formatBytes } from "~/lib/utils.ts";
 
-export const meta = () => [{ title: "下载队列 · UHD 媒体自动化控制台" }];
+export const meta = () => [{ title: "下载面板 · UHD 媒体自动化控制台" }];
 
 export default function DownloadsPage() {
   const f = useQueryState(["status", "managed"] as const);
@@ -89,7 +90,7 @@ export default function DownloadsPage() {
   return (
     <>
       <PageHeader
-        title="下载队列"
+        title="下载面板"
         description="阈值暂停不能手动绕过;无进展只记录,不自动换源。"
         actions={
           <Button variant="outline" size="sm" onClick={() => void qc.invalidateQueries({ queryKey: ["downloads"] })}>
@@ -98,6 +99,7 @@ export default function DownloadsPage() {
           </Button>
         }
       />
+      <DownloadsTabs />
       <CacheVolumes />
       <FilterBar onReset={f.active ? f.reset : undefined}>
         <FilterSelect