feat(cache): PG kv_cache ported from MP TTLCache, TMDB request and recognize caches

Migration 0042_cache adds UNLOGGED kv_cache. PgCache mirrors MP
runtime/cache.py (region, per-key TTL, TLRU maxsize eviction, @cached as
cachedCall); only the storage moves from memory to PG. TMDB request
responses (MP TMDb.request @cached) and recognize results (MP TmdbCache:
same key, {id:0} negative cache with EMPTY_RESULT_CACHE_TTL, type-conflict
checks, backfill after manual assignment) live in kv_cache, shared by all
processes. Settings cache.tmdbTtlHours / tmdbMaxSize / emptyResultTtlSec
map to META_CACHE_EXPIRE / CONF.tmdb / EMPTY_RESULT_CACHE_TTL. TMDB
details now also store posterPath / backdropPath.

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

packages/contracts/src/search.ts

@@ -52,6 +52,8 @@ export const TmdbCandidate = z.object({
   year: z.number().int().nullable(),
   overview: z.string().nullable(),
   popularity: z.number().nullable(),
+  /** TMDB poster_path;前端经图片代理显示海报 */
+  posterPath: z.string().nullable().optional(),
   /** 已有本地作品接受了这个 TMDB 身份时给出(跟随合并跳转),前端显示"查看"而不是"订阅" */
   localEntityId: Id.nullable(),
 });