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/metadata/normalizer.py

@@ -96,6 +96,23 @@ def company_logo_artwork(logo_path: str | None) -> NormalizedArtwork | None:
     )
 
 
+@dataclass
+class NormalizedAlternateTitle:
+    title: str
+    country_code: str | None
+    type: str | None = None
+
+
+def _alternate_titles(entries: list[dict]) -> list[NormalizedAlternateTitle]:
+    return [
+        NormalizedAlternateTitle(
+            title=t["title"], country_code=t.get("iso_3166_1") or None, type=t.get("type") or None
+        )
+        for t in entries
+        if t.get("title")
+    ]
+
+
 # TMDb's per-country rating body isn't returned alongside a release_dates
 # certification or a content_ratings rating -- only the country and the
 # rating string itself are. This maps the handful of markets Aurora can
@@ -216,7 +233,7 @@ class NormalizedMovie:
     adult: bool
     genres: list[str] = field(default_factory=list)
     keywords: list[str] = field(default_factory=list)
-    alternate_titles: list[str] = field(default_factory=list)
+    alternate_titles: list[NormalizedAlternateTitle] = field(default_factory=list)
     companies: list[NormalizedCompanyRef] = field(default_factory=list)
     cast: list[NormalizedPersonRef] = field(default_factory=list)
     crew: list[NormalizedPersonRef] = field(default_factory=list)
@@ -419,7 +436,7 @@ def normalize_movie(raw: dict) -> NormalizedMovie:
         adult=bool(raw.get("adult", False)),
         genres=[g["name"] for g in raw.get("genres", [])],
         keywords=[k["name"] for k in keywords],
-        alternate_titles=[t["title"] for t in alt_titles if t.get("title")],
+        alternate_titles=_alternate_titles(alt_titles),
         companies=companies,
         cast=cast,
         crew=crew,
@@ -567,7 +584,7 @@ class NormalizedSeries:
     vote_count: int | None
     genres: list[str] = field(default_factory=list)
     keywords: list[str] = field(default_factory=list)
-    alternate_titles: list[str] = field(default_factory=list)
+    alternate_titles: list[NormalizedAlternateTitle] = field(default_factory=list)
     networks: list[NormalizedCompanyRef] = field(default_factory=list)
     companies: list[NormalizedCompanyRef] = field(default_factory=list)
     creators: list[NormalizedPersonRef] = field(default_factory=list)
@@ -748,7 +765,7 @@ def normalize_series(raw: dict) -> NormalizedSeries:
         vote_count=raw.get("vote_count"),
         genres=[g["name"] for g in raw.get("genres", [])],
         keywords=[k["name"] for k in keywords],
-        alternate_titles=[t["title"] for t in alt_titles if t.get("title")],
+        alternate_titles=_alternate_titles(alt_titles),
         networks=networks,
         companies=companies,
         creators=creators,