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- Removed obsolete *_edge_cases test files superseded by structured tests.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.

tests/test_api.py

@@ -1,4 +1,21 @@
-"""Tests for FastAPI endpoints."""
+"""Tests for the FastAPI endpoints exposed by ``alfred.app``.
+
+Covers the OpenAI-compatible surface that LibreChat consumes:
+
+- ``GET /health`` — version + status.
+- ``GET /v1/models`` — single ``agent-media`` entry.
+- ``POST /v1/chat/completions`` — both blocking and streaming modes,
+  request validation (empty messages, missing user role, invalid JSON),
+  and the OpenAI-compatible response envelope (``choices[0].message``).
+- ``GET /memory/state`` and ``GET /memory/episodic/search-results`` —
+  debug introspection endpoints.
+- ``POST /memory/clear-session`` — STM/episodic reset.
+
+Tests patch ``alfred.app.agent.step`` rather than running the real LLM.
+The app module degrades gracefully when no LLM provider is configured at
+import time (placeholder LLM that 503s on use), which is what lets these
+tests collect under pytest without ``DEEPSEEK_API_KEY``.
+"""
 
 from unittest.mock import patch