Add trending movies/series, refreshed on a schedule

Mirrors TMDb's own /trending/{movie|tv}/{day|week} ranking rather than
Aurora computing trending itself from popularity deltas -- that would
require re-syncing the entire catalog on a schedule, infeasible at any
real scale, whereas TMDb already computes this well from signals (real
view/search velocity) Aurora has no access to.

New: TrendingEntry model + migration 0003, MetadataProvider.get_trending
(concrete/optional, like aclose(), so existing test fakes don't all need
updating), refresh_trending() which actually ingests each trending item
(only ~20 per window, cheap enough to fully ingest rather than apply the
never-fabricate-a-stub rule recommendations uses), a twice-daily arq cron
job (WorkerSettings.cron_jobs, new to this codebase), a manual admin
trigger for right after a deploy, and GET /movies/trending + GET
/series/trending.

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

app/providers/base.py

@@ -70,5 +70,16 @@ class MetadataProvider(ABC):
         """Search this provider's catalog for movies matching `query`. Used
         to seed ingestion, not exposed directly to API clients."""
 
+    async def get_trending(self, media_type: str, time_window: str) -> list[dict[str, Any]]:
+        """Fetch a ranked list of raw items (movies or series, per
+        `media_type`) currently trending over `time_window` ("day" |
+        "week"). Not every provider has a trending concept, so this is
+        concrete rather than abstract (like `aclose` below) — a provider
+        that doesn't support it simply doesn't override this, and callers
+        get an empty list rather than every other provider implementation
+        having to stub out a method that means nothing for them."""
+
+        return []
+
     async def aclose(self) -> None:
         """Release any held resources (HTTP clients, ...). Optional."""

app/providers/tmdb.py

@@ -124,6 +124,13 @@ class TMDbProvider(MetadataProvider):
         data = await self._get("/search/movie", {"query": query})
         return data.get("results", [])
 
+    async def get_trending(self, media_type: str, time_window: str) -> list[dict[str, Any]]:
+        # TMDb's own endpoint shape: /trending/{movie|tv}/{day|week} -- page
+        # 1 only (~20 results), enough for a trending rail without pulling
+        # in TMDb's full multi-page trending list.
+        data = await self._get(f"/trending/{media_type}/{time_window}")
+        return data.get("results", [])
+
     async def aclose(self) -> None:
         if self._owns_client:
             await self._client.aclose()