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/services/movie_service.py

@@ -24,6 +24,7 @@ from app.services.common import (
     pick_certification,
     primary_artwork_path,
     split_credits,
+    to_alternate_title_out,
     to_images_out,
     to_release_date_out,
     to_video_out,
@@ -53,6 +54,7 @@ async def get_movie_detail(session: AsyncSession, movie_aurora_id: str) -> Movie
 
     genres = await movie_repository.get_movie_genres(session, movie_id)
     keywords = await movie_repository.get_movie_keywords(session, movie_id)
+    alternate_titles = await movie_repository.get_movie_alternate_titles(session, movie_id)
     companies = await movie_repository.get_movie_companies(session, movie_id)
     credits_ = await polymorphic.get_credits(session, "movie", movie_id)
     artwork = await polymorphic.get_artwork(session, "movie", movie_id)
@@ -104,6 +106,7 @@ async def get_movie_detail(session: AsyncSession, movie_aurora_id: str) -> Movie
         certification=pick_certification(release_dates),
         genres=[GenreOut(id=aurora_id("genre", str(g.id)), name=g.name) for g in genres],
         keywords=[KeywordOut(id=aurora_id("keyword", str(k.id)), name=k.name) for k in keywords],
+        alternate_titles=[to_alternate_title_out(t) for t in alternate_titles],
         cast=cast,
         crew=crew,
         companies=company_out,
@@ -193,6 +196,7 @@ async def list_movies(
     session: AsyncSession,
     *,
     genre_aurora_id: str | None,
+    keyword_aurora_id: str | None,
     year: int | None,
     status: str | None,
     sort_by: str,
@@ -207,6 +211,13 @@ async def list_movies(
         except ValueError as exc:
             raise InvalidMovieFilterError(f"invalid genre id: {genre_aurora_id!r}") from exc
 
+    keyword_id: uuid.UUID | None = None
+    if keyword_aurora_id is not None:
+        try:
+            keyword_id = uuid.UUID(parse_aurora_id(keyword_aurora_id, expected_type="keyword"))
+        except ValueError as exc:
+            raise InvalidMovieFilterError(f"invalid keyword id: {keyword_aurora_id!r}") from exc
+
     status_enum: MovieStatus | None = None
     if status is not None:
         try:
@@ -217,6 +228,7 @@ async def list_movies(
     movies, total = await movie_repository.list_movies(
         session,
         genre_id=genre_id,
+        keyword_id=keyword_id,
         year=year,
         status=status_enum,
         sort_by=sort_by,