chore: sprint cleanup — language unification, parser unification, fossils removal

Several weeks of work accumulated without being committed. Grouped here for
clarity; see CHANGELOG.md [Unreleased] for the user-facing summary.

Highlights
----------

P1 #2 — ISO 639-2/B canonical migration
- New Language VO + LanguageRegistry (alfred/domain/shared/knowledge/).
- iso_languages.yaml as single source of truth for language codes.
- SubtitleKnowledgeBase now delegates lookup to LanguageRegistry; subtitles.yaml
  only declares subtitle-specific tokens (vostfr, vf, vff, …).
- SubtitlePreferences default → ["fre", "eng"]; subtitle filenames written as
  {iso639_2b}.srt (legacy fr.srt still read via alias).
- Scanner: dropped _LANG_KEYWORDS / _SDH_TOKENS / _FORCED_TOKENS /
  SUBTITLE_EXTENSIONS hardcoded dicts.
- Fixed: 'hi' token no longer marks SDH (conflicted with Hindi alias).
- Added settings.min_movie_size_bytes (was a module constant).

P1 #3 — Release parser unification + data-driven tokenizer
- parse_release() is now the single source of truth for release-name parsing.
- alfred/knowledge/release/separators.yaml declares the token separators used
  by the tokenizer (., space, [, ], (, ), _). New conventions can be added
  without code changes.
- Tokenizer now splits on any configured separator instead of name.split('.').
  Releases like 'The Father (2020) [1080p] [WEBRip] [5.1] [YTS.MX]' parse via
  the direct path without sanitization fallback.
- Site-tag extraction always runs first; well-formedness only rejects truly
  forbidden chars.
- _parse_season_episode() extended with NxNN / NxNNxNN alt forms.
- Removed dead helpers: _sanitize, _normalize.

Domain cleanup
- Deleted fossil services with zero production callers:
    alfred/domain/movies/services.py
    alfred/domain/tv_shows/services.py
    alfred/domain/subtitles/services.py (replaced by subtitles/services/ package)
    alfred/domain/subtitles/repositories.py
- Split monolithic subtitle services into a package (identifier, matcher,
  placer, pattern_detector, utils) + dedicated knowledge/ package.
- MediaInfo split into dedicated package (alfred/domain/shared/media/:
  audio, video, subtitle, info, matching).

Persistence cleanup
- Removed dead JSON repositories (movie/subtitle/tvshow_repository.py).

Tests
- Major expansion of the test suite organized to mirror the source tree.
- Removed obsolete *_edge_cases test files superseded by structured tests.
- Suite: 990 passed, 8 skipped.

Misc
- .gitignore: exclude env_backup/ and *.bak.
- Adjustments across agent/llm, app.py, application/filesystem, and
  infrastructure/filesystem to align with the new domain layout.

alfred/infrastructure/filesystem/ffprobe.py

@@ -7,7 +7,7 @@ import logging
 import subprocess
 from pathlib import Path
 
-from alfred.domain.shared.media_info import AudioTrack, MediaInfo, SubtitleTrack
+from alfred.domain.shared.media import AudioTrack, MediaInfo, SubtitleTrack, VideoTrack
 
 logger = logging.getLogger(__name__)
 
@@ -58,7 +58,7 @@ def _parse(data: dict) -> MediaInfo:
 
     info = MediaInfo()
 
-    # Format-level
+    # File-level duration/bitrate (ffprobe ``format`` block — independent of streams)
     if "duration" in fmt:
         try:
             info.duration_seconds = float(fmt["duration"])
@@ -73,10 +73,16 @@ def _parse(data: dict) -> MediaInfo:
     for stream in streams:
         codec_type = stream.get("codec_type")
 
-        if codec_type == "video" and info.video_codec is None:
-            info.video_codec = stream.get("codec_name")
-            info.width = stream.get("width")
-            info.height = stream.get("height")
+        if codec_type == "video":
+            info.video_tracks.append(
+                VideoTrack(
+                    index=stream.get("index", len(info.video_tracks)),
+                    codec=stream.get("codec_name"),
+                    width=stream.get("width"),
+                    height=stream.get("height"),
+                    is_default=stream.get("disposition", {}).get("default", 0) == 1,
+                )
+            )
 
         elif codec_type == "audio":
             info.audio_tracks.append(