Add keyword browsing/filtering and expose alternate titles

Keywords were ingested and shown read-only on detail pages, but had no
directory (GET /keywords) or filter param -- the same gap genres had
before today. Mirrors the genre browse pattern exactly: repository,
service, route, plus a `keyword` filter on GET /movies and GET /series.

Alternate/translated titles ("Also Known As") were normalized down to
bare title strings and never written to MovieAlternateTitle/
SeriesAlternateTitle at all. Normalizer now captures country_code + type
per TMDb's actual shape; ingestion writes them; movie/series detail now
expose an alternate_titles list.

Co-Authored-By: Claude Sonnet 5 <[email protected]>

tests/integration/test_series_browse.py

@@ -13,6 +13,7 @@ from sqlalchemy.ext.asyncio import AsyncSession
 
 from app.core.ids import aurora_id
 from app.models.genre import Genre
+from app.models.keyword import Keyword
 from app.services import tv_service
 from app.services.ingestion.series_ingestion import ingest_series
 from tests.integration.test_series_ingestion import FakeTMDbSeriesProvider
@@ -41,6 +42,7 @@ async def _seed_series(db_session: AsyncSession) -> None:
             popularity=90.0,
             vote_average=8.0,
             first_air_date="2021-01-01",
+            keywords={"results": [{"id": 1, "name": "anthology"}]},
         ),
         _series_payload(
             id=9103,
@@ -72,6 +74,13 @@ async def _genre_aurora_id(db_session: AsyncSession, name: str) -> str:
     return aurora_id("genre", str(genre.id))
 
 
+async def _keyword_aurora_id(db_session: AsyncSession, name: str) -> str:
+    keyword = (
+        await db_session.execute(select(Keyword).where(Keyword.name == name))
+    ).scalar_one()
+    return aurora_id("keyword", str(keyword.id))
+
+
 @pytest.mark.asyncio
 async def test_list_series_defaults_to_popularity_descending(db_session: AsyncSession):
     await _seed_series(db_session)
@@ -79,6 +88,7 @@ async def test_list_series_defaults_to_popularity_descending(db_session: AsyncSe
     out = await tv_service.list_series(
         db_session,
         genre_aurora_id=None,
+        keyword_aurora_id=None,
         year=None,
         status=None,
         sort_by="popularity",
@@ -105,6 +115,7 @@ async def test_list_series_filters_by_genre(db_session: AsyncSession):
     out = await tv_service.list_series(
         db_session,
         genre_aurora_id=drama_id,
+        keyword_aurora_id=None,
         year=None,
         status=None,
         sort_by="popularity",
@@ -117,6 +128,42 @@ async def test_list_series_filters_by_genre(db_session: AsyncSession):
     assert {s.title for s in out.results} == {"B Drama Show", "D Planned Show", "A Drama Show"}
 
 
+@pytest.mark.asyncio
+async def test_list_series_filters_by_keyword(db_session: AsyncSession):
+    await _seed_series(db_session)
+    anthology_id = await _keyword_aurora_id(db_session, "anthology")
+
+    out = await tv_service.list_series(
+        db_session,
+        genre_aurora_id=None,
+        keyword_aurora_id=anthology_id,
+        year=None,
+        status=None,
+        sort_by="popularity",
+        sort_dir="desc",
+        page=1,
+        page_size=20,
+    )
+
+    assert [s.title for s in out.results] == ["B Drama Show"]
+
+
+@pytest.mark.asyncio
+async def test_list_series_rejects_malformed_keyword_filter(db_session: AsyncSession):
+    with pytest.raises(tv_service.InvalidSeriesFilterError):
+        await tv_service.list_series(
+            db_session,
+            genre_aurora_id=None,
+            keyword_aurora_id="not-an-aurora-id",
+            year=None,
+            status=None,
+            sort_by="popularity",
+            sort_dir="desc",
+            page=1,
+            page_size=20,
+        )
+
+
 @pytest.mark.asyncio
 async def test_list_series_filters_by_year(db_session: AsyncSession):
     await _seed_series(db_session)
@@ -124,6 +171,7 @@ async def test_list_series_filters_by_year(db_session: AsyncSession):
     out = await tv_service.list_series(
         db_session,
         genre_aurora_id=None,
+        keyword_aurora_id=None,
         year=2020,
         status=None,
         sort_by="popularity",
@@ -142,6 +190,7 @@ async def test_list_series_filters_by_status(db_session: AsyncSession):
     out = await tv_service.list_series(
         db_session,
         genre_aurora_id=None,
+        keyword_aurora_id=None,
         year=None,
         status="planned",
         sort_by="popularity",
@@ -160,6 +209,7 @@ async def test_list_series_paginates(db_session: AsyncSession):
     page1 = await tv_service.list_series(
         db_session,
         genre_aurora_id=None,
+        keyword_aurora_id=None,
         year=None,
         status=None,
         sort_by="popularity",
@@ -170,6 +220,7 @@ async def test_list_series_paginates(db_session: AsyncSession):
     page2 = await tv_service.list_series(
         db_session,
         genre_aurora_id=None,
+        keyword_aurora_id=None,
         year=None,
         status=None,
         sort_by="popularity",
@@ -190,6 +241,7 @@ async def test_list_series_rejects_malformed_genre_filter(db_session: AsyncSessi
         await tv_service.list_series(
             db_session,
             genre_aurora_id="not-an-aurora-id",
+            keyword_aurora_id=None,
             year=None,
             status=None,
             sort_by="popularity",
@@ -205,6 +257,7 @@ async def test_list_series_rejects_unknown_status_filter(db_session: AsyncSessio
         await tv_service.list_series(
             db_session,
             genre_aurora_id=None,
+            keyword_aurora_id=None,
             year=None,
             status="not_a_real_status",
             sort_by="popularity",