feat(adapters): qBittorrent, filesystem, TMDB and Emby adapters with testkit mocks (W1-3a)

- qbittorrent: WebUI API v2 client (cookie/API-key auth, add/info/files/filePrio,
  pause/resume with 5.x stop/start fallback, tags, delete with explicit deleteFiles,
  maindata), error classes, idempotent submit with local infohash (own bencode)
  and post-timeout hash/probe-tag lookup; state mapping per MoviePilot
- fs: copyWithVerify (tmp + fsync + size/sha256/sample + no-clobber commit),
  moveSafe (EXDEV surfaced), resumable crossDeviceMove, statSafe/checkRoot with
  root sentinel, budgeted incremental scan with cursor, ffprobe, statfs usage
- tmdb: multi-language search/details/seasons, LRU+TTL cache with coalescing,
  rate-limit backoff, MoviePilot match chain (name normalization, year +-1)
- emby: Emby/Jellyfin items/seasons/episodes/MediaSources, failures -> unknown
- testkit: mock qB / TMDB / Emby servers, torrent builder, temp-tree fixtures
- docs: W1-3a porting table appended to downloader-and-sites ledger

Co-Authored-By: Claude Fable 5.1 <[email protected]>

packages/adapters/src/tmdb/README.md

@@ -0,0 +1,5 @@
+# tmdb
+
+TMDB v3 查询:多语言搜索(默认 zh-CN + en-US,按 ID 合并标题)、`searchMulti`、详情(别名 alternative_titles、译名 translations、外部 ID、季列表)、季集列表;内存 LRU + TTL 缓存(默认 1024 条/24h,空结果 30min)与并发合并,并发/间隔限流,429 按 Retry-After 退避。输出归一化候选 `MetadataCandidate`(provider `tmdb`,entityType,externalId,titles,year,aliases,seasons?)。`matchTmdb`/`matchTmdbMulti` 迁移 MoviePilot 的匹配链(名称规范化后完全相等、年份 ±1、季年份优先、别名/译名回退)。错误为 `TmdbError`(auth/network/timeout/notfound/rate/protocol),不会把查询失败当成无结果。
+
+仅对 mock 与官方 API 文档验证,未连接真实实例。