refactor(tmdb): ACL pass — push VOs into DTOs, split search per media type

Anti-corruption boundary tightened on the TMDB adapter:

* TmdbMovieInfo / TmdbShowInfo now carry domain VOs (TmdbId, ImdbId,
  MovieTitle, ReleaseYear, ShowStatus) instead of raw scalars —
  validation happens at the boundary, not three layers later.
* ShowStatus enum added (domain/tv_shows/value_objects) with a
  from_tmdb() mapper that falls back to UNKNOWN + logs a warning on
  unrecognized values. TVShow.status is now ShowStatus, not str.
* MovieTitle cap raised from 100 to 150 chars.
* MediaResult / ExternalIds dropped. Replaced by per-media search
  DTOs: TmdbMovieSearchResult and TmdbShowSearchResult. Neither
  carries imdb_id — search no longer enriches with external_ids
  (callers needing imdb_id follow up with get_movie_info /
  get_tv_show_info on the chosen tmdb_id).
* TMDBClient: search_multi / search_media / _parse_result removed.
  search_movies (/search/movie) and search_shows (/search/tv) added,
  each parsing hits into VO-typed DTOs.
* SearchMovieUseCase returns a list of MovieHit (flattened to
  primitives for the agent). New symmetric SearchShowUseCase +
  ShowHit / SearchShowResponse DTOs.
* agent/tools/api.py: find_media_imdb_id → search_movies +
  search_shows wrappers.
* FileEntry moved from domain/shared/ports/filesystem_scanner.py to
  domain/shared/file_entry.py (it's a DTO, not a Protocol); size_kb
  (float) → size (int bytes). Scanner and SubtitleIdentifier
  updated.

Tests: 79/79 pass on tests/infrastructure/api/ +
tests/application/test_search_movie.py +
tests/application/test_search_show.py.

tests/application/test_search_show.py

@@ -0,0 +1,101 @@
+"""Tests for ``alfred.application.tv_shows.search_show.SearchShowUseCase``.
+
+Symmetric to ``test_search_movie.py``. The use case wraps
+:meth:`TMDBClient.search_shows` and flattens each hit into a
+:class:`ShowHit` wrapped in a :class:`SearchShowResponse` envelope.
+"""
+
+from __future__ import annotations
+
+from unittest.mock import MagicMock
+
+import pytest
+
+from alfred.application.tv_shows.search_show import SearchShowUseCase
+from alfred.domain.shared.value_objects import TmdbId
+from alfred.infrastructure.api.tmdb.dto import TmdbShowSearchResult
+from alfred.infrastructure.api.tmdb.exceptions import (
+    TMDBAPIError,
+    TMDBConfigurationError,
+)
+
+
+@pytest.fixture
+def client():
+    return MagicMock()
+
+
+@pytest.fixture
+def use_case(client):
+    return SearchShowUseCase(client)
+
+
+def _hit(**kw) -> TmdbShowSearchResult:
+    defaults = dict(
+        tmdb_id=TmdbId(84958),
+        name="Foundation",
+        first_air_year=2021,
+    )
+    defaults.update(kw)
+    return TmdbShowSearchResult(**defaults)
+
+
+class TestSuccess:
+    def test_single_hit_is_flattened(self, client, use_case):
+        client.search_shows.return_value = [_hit()]
+        r = use_case.execute("Foundation")
+        assert r.status == "ok"
+        assert len(r.hits) == 1
+        h = r.hits[0]
+        assert h.tmdb_id == 84958
+        assert h.name == "Foundation"
+        assert h.first_air_year == 2021
+
+    def test_multiple_hits_preserve_order(self, client, use_case):
+        client.search_shows.return_value = [
+            _hit(),
+            _hit(tmdb_id=TmdbId(42), name="Fallout"),
+        ]
+        r = use_case.execute("Foundation")
+        assert [h.tmdb_id for h in r.hits] == [84958, 42]
+
+    def test_hit_without_first_air_year(self, client, use_case):
+        client.search_shows.return_value = [_hit(first_air_year=None)]
+        r = use_case.execute("Foundation")
+        assert r.hits[0].first_air_year is None
+
+    def test_empty_results_returns_ok_with_no_hits(self, client, use_case):
+        client.search_shows.return_value = []
+        r = use_case.execute("nothing")
+        assert r.status == "ok"
+        assert r.hits == []
+        assert r.error is None
+
+
+class TestErrorTranslation:
+    def test_configuration_error(self, client, use_case):
+        client.search_shows.side_effect = TMDBConfigurationError("missing key")
+        r = use_case.execute("x")
+        assert r.status == "error"
+        assert r.error == "configuration_error"
+
+    def test_api_error(self, client, use_case):
+        client.search_shows.side_effect = TMDBAPIError("500 oops")
+        r = use_case.execute("x")
+        assert r.status == "error"
+        assert r.error == "api_error"
+        assert "500" in r.message
+
+    def test_validation_error(self, client, use_case):
+        client.search_shows.side_effect = ValueError("query too long")
+        r = use_case.execute("x")
+        assert r.status == "error"
+        assert r.error == "validation_failed"
+        assert "too long" in r.message
+
+
+class TestPassThrough:
+    def test_query_forwarded_verbatim(self, client, use_case):
+        client.search_shows.return_value = []
+        use_case.execute("Foundation")
+        client.search_shows.assert_called_once_with("Foundation")