feat: ffprobe + TMDb scrape + HLS transcode + history/favourites/playlists

Backend
  - service/ffprobe.go: thin ffprobe wrapper, parses duration / resolution /
    codecs into a typed ProbeResult. 30s per-file timeout.
  - service/tmdb.go: minimal TMDb provider (search/movie). Disabled when no
    api key; supports tmdb_api_proxy / tmdb_image_proxy overrides for users
    behind a firewall.
  - service/scraper.go: filename cleaner (handles bracketed tags, scene
    noise tokens, year extraction), per-row + per-library enrichment with a
    4 RPS throttle and WS hub progress events. Unit-tested.
  - service/scanner.go: now invokes ffprobe per file and kicks the TMDb
    scraper in the background once a library scan finishes.
  - service/transcoder.go: per-media ffmpeg HLS job manager; outputs
    index.m3u8 + seg_NNNNN.ts under cache/hls/<id>; cancels jobs on
    shutdown; publishes 'transcode' WS events.
  - service/stream.go: serves HLS playlist (with 30s wait-for-ready) and
    .ts segments with path-traversal protection. Adds Probe() helper used
    by the admin 'reprobe' button.
  - service/image_proxy.go: cached, host-allow-listed reverse proxy for
    TMDb / Bangumi / Douban / Fanart / TheTVDB images so the SPA never
    hits a CORS or GFW issue.
  - service/playback.go: history upsert, favourites toggle, playlist CRUD
    + ordered items. RecentHistory joins with model.Media in one extra
    query so the home page can render a 'Continue Watching' row.
  - handler/streaming.go + handler/playback.go: REST endpoints for HLS,
    image proxy, scrape (one + library), reprobe, history, favourites,
    playlists.
  - handler/handler.go: registers /api/hls/:id/{index.m3u8,:seg}, /api/img,
    /api/history, /api/favourites/:id, /api/playlists/* with proper
    auth/admin guards.

Frontend
  - api/client.ts: imageURL() helper; hlsURL() endpoint; reuses the JWT in
    a query parameter for <video src> and <img src>.
  - api/playback.ts: typed helpers for history, favourites, playlists.
  - components/MediaCard.tsx: optional 'progress' prop renders a thin
    bottom progress bar, used by the new Continue Watching row.
  - pages/HomePage.tsx: two rows (Continue Watching + Recently Added);
    falls back to the empty-state hint when both are empty.
  - pages/PlayerPage.tsx: hls.js (lazy-imported) with auto-fallback to
    direct play; ?mode=hls|direct query toggle; resume position written
    every 10s while playing.
  - pages/MediaDetailPage.tsx: heart toggle + admin 'rescrape' / 'reprobe'
    buttons + dedicated 'HLS 转码播放' CTA.
  - pages/FavouritesPage.tsx, PlaylistsPage.tsx, PlaylistDetailPage.tsx:
    new screens.
  - components/Layout.tsx + App.tsx: sidebar links for Favourites and
    Playlists; routes are now lazily code-split via React.lazy + Suspense
    so the initial bundle stays at ~243 KB / 82 KB gzipped (hls.js is
    fetched only on first HLS playback).

Verified: go build, go vet, go test (incl. CleanQuery cases) all pass;
frontend tsc -b && vite build emits 9 route chunks plus a deferred hls
chunk.

web/src/App.tsx

@@ -1,56 +1,71 @@
+import { Suspense, lazy } from 'react'
 import { Navigate, Route, Routes } from 'react-router-dom'
 
 import { Layout } from './components/Layout'
-import { RequireAuth, RequireAdmin } from './components/RequireAuth'
-import { AdminPage } from './pages/AdminPage'
-import { HomePage } from './pages/HomePage'
-import { LibraryPage } from './pages/LibraryPage'
+import { RequireAdmin, RequireAuth } from './components/RequireAuth'
 import { LoginPage } from './pages/LoginPage'
-import { MediaDetailPage } from './pages/MediaDetailPage'
-import { PlayerPage } from './pages/PlayerPage'
-import { SearchPage } from './pages/SearchPage'
 
-// Top-level route table.
-//
-// Public:
-//   /login
-//
-// Authenticated:
-//   /                      → home (continue watching + recently added)
-//   /library/:id           → library content grid
-//   /search                → keyword search
-//   /media/:id             → media detail
-//   /play/:id              → fullscreen player
-//
-// Admin only:
-//   /admin                 → users / settings / activity log
+// Lazy-loaded routes — the login screen and the layout shell ship in the
+// initial bundle; everything else is fetched on first navigation.
+const HomePage = lazy(() => import('./pages/HomePage').then((m) => ({ default: m.HomePage })))
+const LibraryPage = lazy(() =>
+  import('./pages/LibraryPage').then((m) => ({ default: m.LibraryPage })),
+)
+const SearchPage = lazy(() =>
+  import('./pages/SearchPage').then((m) => ({ default: m.SearchPage })),
+)
+const FavouritesPage = lazy(() =>
+  import('./pages/FavouritesPage').then((m) => ({ default: m.FavouritesPage })),
+)
+const PlaylistsPage = lazy(() =>
+  import('./pages/PlaylistsPage').then((m) => ({ default: m.PlaylistsPage })),
+)
+const PlaylistDetailPage = lazy(() =>
+  import('./pages/PlaylistDetailPage').then((m) => ({ default: m.PlaylistDetailPage })),
+)
+const MediaDetailPage = lazy(() =>
+  import('./pages/MediaDetailPage').then((m) => ({ default: m.MediaDetailPage })),
+)
+const PlayerPage = lazy(() =>
+  import('./pages/PlayerPage').then((m) => ({ default: m.PlayerPage })),
+)
+const AdminPage = lazy(() => import('./pages/AdminPage').then((m) => ({ default: m.AdminPage })))
+
+// Fallback shown while a chunk is loading.
+const Loading = () => <p className="px-6 py-8 text-slate-500">加载中…</p>
+
 export default function App() {
   return (
-    <Routes>
-      <Route path="/login" element={<LoginPage />} />
-      <Route
-        path="/"
-        element={
-          <RequireAuth>
-            <Layout />
-          </RequireAuth>
-        }
-      >
-        <Route index element={<HomePage />} />
-        <Route path="library/:id" element={<LibraryPage />} />
-        <Route path="search" element={<SearchPage />} />
-        <Route path="media/:id" element={<MediaDetailPage />} />
-        <Route path="play/:id" element={<PlayerPage />} />
+    <Suspense fallback={<Loading />}>
+      <Routes>
+        <Route path="/login" element={<LoginPage />} />
         <Route
-          path="admin"
+          path="/"
           element={
-            <RequireAdmin>
-              <AdminPage />
-            </RequireAdmin>
+            <RequireAuth>
+              <Layout />
+            </RequireAuth>
           }
-        />
-      </Route>
-      <Route path="*" element={<Navigate to="/" replace />} />
-    </Routes>
+        >
+          <Route index element={<HomePage />} />
+          <Route path="library/:id" element={<LibraryPage />} />
+          <Route path="search" element={<SearchPage />} />
+          <Route path="favourites" element={<FavouritesPage />} />
+          <Route path="playlists" element={<PlaylistsPage />} />
+          <Route path="playlist/:id" element={<PlaylistDetailPage />} />
+          <Route path="media/:id" element={<MediaDetailPage />} />
+          <Route path="play/:id" element={<PlayerPage />} />
+          <Route
+            path="admin"
+            element={
+              <RequireAdmin>
+                <AdminPage />
+              </RequireAdmin>
+            }
+          />
+        </Route>
+        <Route path="*" element={<Navigate to="/" replace />} />
+      </Routes>
+    </Suspense>
   )
 }