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]>

app/api/v1/series.py

@@ -29,6 +29,7 @@ router = APIRouter(prefix="/series", tags=["series"], dependencies=[Depends(enfo
 @router.get("", response_model=SeriesListOut)
 async def list_series(
     genre: str | None = Query(None, description="Aurora genre id, e.g. aur_genre_..."),
+    keyword: str | None = Query(None, description="Aurora keyword id, e.g. aur_keyword_..."),
     year: int | None = Query(None, description="First air date year"),
     status_: str | None = Query(None, alias="status", description="Series status, e.g. ended"),
     sort_by: Literal["popularity", "first_air_date", "vote_average", "title"] = Query("popularity"),
@@ -41,6 +42,7 @@ async def list_series(
         return await tv_service.list_series(
             session,
             genre_aurora_id=genre,
+            keyword_aurora_id=keyword,
             year=year,
             status=status_,
             sort_by=sort_by,