feat(cache): TMDB image proxy, posters, cache admin API and settings cards

GET /img/tmdb/{size}/{file} ported from MP ImageHelper / fetch_image
(sanitized cache path under DATA_DIR/cache/images, GLOBAL_IMAGE_CACHE
read switch, md5 ETag / 304, day-based cleanup job). Cache module adds
cache.sweep / cache.images_clean jobs and /cache/tmdb, /cache/images
list and clear endpoints. Library list/detail and the search palette
show posters with the neutral placeholder as fallback; metadata settings
get TMDB cache and image cache cards. Runbook docs/runbook/cache.md and
porting notes docs/porting/moviepilot-tmdb-cache.md.

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

apps/web/app/routes/console/library.$id.tsx

@@ -51,7 +51,16 @@ import {
   UNIT_KIND,
   VERIFY_STATUS,
 } from "~/components/library/labels.ts";
-import { Chip, ChipList, CoverPlaceholder, Panel, ProgressLine, relTime, Tone } from "~/components/library/parts.tsx";
+import {
+  Chip,
+  ChipList,
+  CoverPlaceholder,
+  Panel,
+  ProgressLine,
+  posterPathOf,
+  relTime,
+  Tone,
+} from "~/components/library/parts.tsx";
 import { SlotCard } from "~/components/library/slot-card.tsx";
 import { EntityNamingButton } from "~/components/naming/entity-naming-dialog.tsx";
 import { Button } from "~/components/ui/button.tsx";
@@ -617,7 +626,12 @@ export default function LibraryDetailPage() {
         <p className="mb-4 text-meta text-muted-foreground">旧 ID {redirected} 已跳转到当前作品。</p>
       ) : null}
       <header className="mb-6 flex flex-wrap items-start gap-4">
-        <CoverPlaceholder title={e.title} kind={e.kind} className="h-28 w-20 sm:h-36 sm:w-24" />
+        <CoverPlaceholder
+          title={e.title}
+          kind={e.kind}
+          posterPath={posterPathOf(e.metadata)}
+          className="h-28 w-20 sm:h-36 sm:w-24"
+        />
         <div className="min-w-0 flex-1 basis-56">
           <div className="flex flex-wrap items-center gap-2">
             <h1 className="min-w-0 text-title-lg font-semibold tracking-tight break-words text-foreground">