refactor(domain): Phase 3 — TVShow/Movie aggregates become TMDB-only

Filesystem-side concerns (file paths, tracks, quality, mode, added_at)
move to the releases/ domain added in Phase 1; the TMDB aggregates now
carry only identity + TMDB catalog facts.

Domain entities:
- TVShow: tmdb_id: TmdbId required (primary key), imdb_id: ImdbId | None
  optional, status: str = "unknown" added.
- Season: episode_count: int = 0 added (TMDB-cached); audio_tracks,
  subtitle_tracks, mode property removed.
- Episode: slimmed to identity + title. file_path/file_size/tracks
  removed. No longer inherits MediaWithTracks.
- Movie: tmdb_id required, imdb_id optional. file_path/file_size/quality/
  added_at/audio_tracks/subtitle_tracks removed. get_filename() now
  returns "Title.Year" — quality moves to MovieRelease.

Builders:
- TVShowBuilder requires tmdb_id: TmdbId; imdb_id/status optional.
- SeasonBuilder.set_episode_count(int) replaces set_audio_tracks /
  set_subtitle_tracks.

No-coercion contract: TVShow(tmdb_id=1396) raises — callers pass
TmdbId(1396). No ergonomic shim per the no-shims rule.

Cascade fixes:
- MediaOrganizer test fixtures updated to new Movie/TVShow shapes.
- Movie.get_filename() re-added (without Quality) so MediaOrganizer
  keeps working until Phase 4 rewires it through MovieRelease.

Quarantined (deleted in Phase 4 alongside v1 dot_alfred):
- tests/application/library/test_rescan.py — module-level skip.
- tests/infrastructure/persistence/dot_alfred/test_repository.py —
  module-level skip.
- tests/infrastructure/persistence/dot_alfred/test_serializer.py —
  module-level skip.

Suite: 1216 passed, 11 skipped (8 pre-existing + 3 Phase 3
quarantines), 4 xfailed. CHANGELOG updated under [Unreleased].

tests/infrastructure/test_filesystem_extras.py

@@ -17,8 +17,8 @@ from __future__ import annotations
 from unittest.mock import MagicMock, patch
 
 from alfred.domain.movies.entities import Movie
-from alfred.domain.movies.value_objects import MovieTitle, Quality, ReleaseYear
-from alfred.domain.shared.value_objects import ImdbId
+from alfred.domain.movies.value_objects import MovieTitle, ReleaseYear
+from alfred.domain.shared.value_objects import ImdbId, TmdbId
 from alfred.domain.tv_shows.entities import Episode, TVShow
 from alfred.domain.tv_shows.value_objects import (
     EpisodeNumber,
@@ -159,17 +159,18 @@ class TestFindVideo:
 
 def _movie() -> Movie:
     return Movie(
-        imdb_id=ImdbId("tt1375666"),
+        tmdb_id=TmdbId(27205),
         title=MovieTitle("Inception"),
+        imdb_id=ImdbId("tt1375666"),
         release_year=ReleaseYear(2010),
-        quality=Quality.HD,
     )
 
 
 def _show() -> TVShow:
     return TVShow(
-        imdb_id=ImdbId("tt0773262"),
+        tmdb_id=TmdbId(2452),
         title="Dexter",
+        imdb_id=ImdbId("tt0773262"),
     )