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- Removed obsolete *_edge_cases test files superseded by structured tests.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/application/test_add_torrent.py

@@ -0,0 +1,111 @@
+"""Tests for ``alfred.application.torrents.add_torrent.AddTorrentUseCase``.
+
+Wraps ``QBittorrentClient.add_torrent`` with magnet-link validation and
+exception translation into an ``AddTorrentResponse`` envelope.
+
+Coverage:
+
+- ``TestValidation`` — empty / non-string / non-magnet rejection.
+- ``TestSuccess`` — client returns True → status="ok".
+- ``TestAddFailure`` — client returns False → status="error", error="add_failed".
+- ``TestErrorTranslation`` — ``QBittorrentAuthError`` → authentication_failed,
+  ``QBittorrentAPIError`` → api_error.
+
+QBittorrentClient is fully mocked.
+"""
+
+from __future__ import annotations
+
+from unittest.mock import MagicMock
+
+import pytest
+
+from alfred.application.torrents.add_torrent import AddTorrentUseCase
+from alfred.infrastructure.api.qbittorrent.exceptions import (
+    QBittorrentAPIError,
+    QBittorrentAuthError,
+)
+
+
+@pytest.fixture
+def client():
+    return MagicMock()
+
+
+@pytest.fixture
+def use_case(client):
+    return AddTorrentUseCase(client)
+
+
+VALID_MAGNET = "magnet:?xt=urn:btih:abc"
+
+
+# --------------------------------------------------------------------------- #
+# Validation                                                                   #
+# --------------------------------------------------------------------------- #
+
+
+class TestValidation:
+    @pytest.mark.parametrize("bad", ["", None, 42, b"magnet:?x"])
+    def test_invalid_inputs_return_validation_failed(self, use_case, client, bad):
+        r = use_case.execute(bad)
+        assert r.status == "error"
+        assert r.error == "validation_failed"
+        client.add_torrent.assert_not_called()
+
+    def test_non_magnet_scheme_rejected(self, use_case, client):
+        r = use_case.execute("http://example.com/torrent")
+        assert r.status == "error"
+        assert r.error == "validation_failed"
+        assert "magnet" in r.message.lower()
+        client.add_torrent.assert_not_called()
+
+
+# --------------------------------------------------------------------------- #
+# Success                                                                      #
+# --------------------------------------------------------------------------- #
+
+
+class TestSuccess:
+    def test_add_success(self, use_case, client):
+        client.add_torrent.return_value = True
+        r = use_case.execute(VALID_MAGNET)
+        assert r.status == "ok"
+        assert r.error is None
+        assert "success" in r.message.lower()
+        client.add_torrent.assert_called_once_with(VALID_MAGNET)
+
+
+# --------------------------------------------------------------------------- #
+# Add failure                                                                  #
+# --------------------------------------------------------------------------- #
+
+
+class TestAddFailure:
+    def test_add_returns_false(self, use_case, client):
+        client.add_torrent.return_value = False
+        r = use_case.execute(VALID_MAGNET)
+        assert r.status == "error"
+        assert r.error == "add_failed"
+
+
+# --------------------------------------------------------------------------- #
+# Error translation                                                            #
+# --------------------------------------------------------------------------- #
+
+
+class TestErrorTranslation:
+    def test_auth_error_translated(self, use_case, client):
+        client.add_torrent.side_effect = QBittorrentAuthError("bad creds")
+        r = use_case.execute(VALID_MAGNET)
+        assert r.status == "error"
+        assert r.error == "authentication_failed"
+        # The message is a fixed user-facing string, not the raw exception.
+        assert "authenticate" in r.message.lower()
+
+    def test_api_error_translated(self, use_case, client):
+        client.add_torrent.side_effect = QBittorrentAPIError("server down")
+        r = use_case.execute(VALID_MAGNET)
+        assert r.status == "error"
+        assert r.error == "api_error"
+        assert "server down" in r.message