fix(jellyseer): resolve request titles via /movie|tv endpoints

The requests table showed all names as "—" because Jellyseerr's /api/v1/request
list does NOT embed titles — they live on the Movie/Series records. Added
JellyseerrClient._resolve_title(media_type, tmdb_id) that fetches
/api/v1/movie/{tmdbId} (→ title) or /api/v1/tv/{tmdbId} (→ name), cached on
the client instance so subsequent polls are instant.

Also scoped the table fetch to open requests only (pending + approved) via
Jellyseerr's filter param, instead of fetching all 800+ historical requests.
open_requests() fetches pending+approved (paginated), resolves their titles
(small set → fast), and returns them sorted by date added desc.

Updated the frontend table's status filter to Open/Pending/Approved (the data
only contains open requests now).

Tests: title resolution end-to-end (movie tmdbId → title), caching across
polls, filter param used. 404/404 backend + 184/184 frontend + build green.

backend/src/media_library_viewer_api/widgets/jellyseerr_stats.py

@@ -107,10 +107,8 @@ def fetch_jellyseer_requests(service: Any) -> list[dict[str, Any]]:
     tab and widgets don't each open a new session.
     """
     base_url = str(service.config.get("jellyseerr_url") or "")
-    api_key = str(
-        (service.secrets or {}).get("jellyseerr_api_key") or service.config.get("jellyseerr_api_key") or ""
-    )
+    api_key = str((service.secrets or {}).get("jellyseerr_api_key") or service.config.get("jellyseerr_api_key") or "")
     if not base_url or not api_key:
         return []
     client = _jellyseer_client((service.id, base_url, api_key))
-    return client.requests(500)
+    return client.open_requests()