feat(contracts,server,web): files G6–G8 fields and identify S-7 contract

- G6: FileRoot.pendingCount/pendingPartial for download roots (same rule as the
  unidentified filter, recursive, cached 5 min, invalidated by files.changed)
- G7: FileEntry.parsedHint from parseReleasePath (file + parent dirs); the web
  subline uses it and no longer parses names itself
- G8: FileIdentifyCandidate.posterUrl (TMDB poster_path via adapter and
  catalog.lookup, local entities from metadata.posterPath); thumbnails in the
  identify panel
- S-7 contract: FilesIdentifyResult.remoteTaskId/remotePending,
  MediaServerInventory.partial, EventType identify.completed with
  IdentifyCompletedPayload; identify panel (useIdentifyLive) and organize wizard
  merge remote results by root + path, buffering events that beat the response

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

packages/testkit/src/tmdb/mock-tmdb.ts

@@ -41,6 +41,7 @@ export async function createMockTmdb(opts: MockTmdbOptions = {}): Promise<MockTm
           original_language: f.original_language,
           overview,
           popularity: f.popularity,
+          poster_path: f.poster_path ?? null,
         }
       : {
           id: f.id,
@@ -51,6 +52,7 @@ export async function createMockTmdb(opts: MockTmdbOptions = {}): Promise<MockTm
           origin_country: f.origin_country,
           overview,
           popularity: f.popularity,
+          poster_path: f.poster_path ?? null,
         };
   };