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/emby/README.md

@@ -0,0 +1,5 @@
+# emby
+
+Emby / Jellyfin 兼容库存查询(`EmbyClient`,`MediaServerRegistry` 管多实例):`/Users` 与查询用户解析(用户名 → 管理员回退)、`/Users/{id}/Items`(IncludeItemTypes、SearchTerm、AnyProviderIdEquals + 客户端复核 ProviderIds)、单条目、`/Shows/{id}/Seasons|Episodes`(排除 Virtual 缺集占位,多集文件展开)、MediaSources 归一化(分辨率/编码/HDR/音轨/字幕/路径/大小,接口没给的字段不补值)。所有查询返回 `ok` 或 `unknown`;`findByProviderId` 只有在查询成功且结果未截断时才给 `not_found`。Emby 走 `/emby` 前缀 + `X-Emby-Token`,Jellyfin 无前缀 + `Authorization: MediaBrowser Token=`。
+
+仅对 mock 与官方 API 文档验证,未连接真实实例。