feat(search): global search aggregation backend (W9-G)

- GET /search?q=&scope=all|media|releases|actions&limit=: local works (title_alias
  exact/prefix/trgm + name prefix, slot status summary), TMDB candidates (cached,
  localEntityId), cross-site releases, page/action jump list; tookMs per group
- cross-site: enabled sites via shared per-site limiter, 15s AbortSignal timeout,
  site concurrency cap 4, same-query coalescing, 30s cache; partial + failedSites;
  results upserted to source_release; inventory overlay via GET /inventory
- GET /search/releases: site/resolution/source/size/free/H&R filters, sort, cursor,
  facets; shares the cache
- POST /search/releases/{siteId}/{siteReleaseId}/plan: forwards in-process to
  POST /acquisition-plans (same auth, validation, audit, rejections)
- contracts/search.ts, runbook, tests (partial/timeout, coalesce, cache, overlay,
  filters/sort, plan)

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

apps/server/src/modules/index.ts

@@ -4,6 +4,7 @@ import { authSettingsModule } from "./auth-settings/index.ts";
 import { fileManagerModule } from "./file-manager/index.ts";
 import { piModule } from "./pi/index.ts";
 import { schedulesModule } from "./schedules/index.ts";
+import { searchModule } from "./search/index.ts";
 import { sourcesIdentityModule } from "./sources-identity/index.ts";
 import type { ServerModule } from "./types.ts";
 
@@ -21,4 +22,5 @@ export const SERVER_MODULES: readonly ServerModule[] = [
   fileManagerModule,
   piModule,
   schedulesModule,
+  searchModule,
 ];