feat(jellyseer): sortable/filterable requests table on the Requests tab

Replace the static "recent requests" list with a proper table of all Jellyseerr
requests, sorted by date added (newest first by default) with standard sorting
and filtering.

Backend:
- JellyseerrClient.requests(max_count=500): paginated GET /api/v1/request
  (sort=added), mapped with type (movie/tv), status, media_status, and
  created_at labels. Returns up to 500 so the table can sort/filter client-side.
- fetch_jellyseer_requests(service) reuses the per-service cached client
  (shared with the stats widgets).
- new GET /api/jellyseerr/requests endpoint.

Frontend:
- JellyseerRequestsTable: TanStack Table (sorting via getSortedRowModel,
  pagination via getPaginationRowModel) reusing the Table primitives +
  TablePagination. Columns: Name / Type / Status / Media / Requested, all
  sortable; default sort Requested desc. A search box filters by name and a
  status dropdown defaults to "Open" (pending+approved+processing) with
  All/Pending/Approved/Declined options. (The shared DataTable is deliberately
  visibility-only, so this is a dedicated sortable table.)
- RequestsTab renders the stats grid + the new table (the compact recent list
  stays on the Requests overview widget).
- useJellyseerRequests hook + fetchJellyseerRequests API client.

Tests: client requests() mapping + single-page stop; fetch helper not-configured;
RequestsTab test mocks both hooks. 404/404 backend + 184/184 frontend pass;
build (tsc -b && vite build) + ESLint clean.

backend/src/media_library_viewer_api/routers/jellyseerr.py

@@ -17,6 +17,7 @@ from media_library_viewer_api.dependencies import get_settings_store
 from media_library_viewer_api.services.service_resolution import resolve_service_record
 from media_library_viewer_api.services.settings_store import SettingsStore
 from media_library_viewer_api.widgets import jellyseerr_stats  # noqa: F401 — ensure provider registration
+from media_library_viewer_api.widgets.jellyseerr_stats import fetch_jellyseer_requests
 from media_library_viewer_api.widgets.stats_provider import get_stats_provider
 
 logger = logging.getLogger(__name__)
@@ -50,3 +51,20 @@ def get_jellyseerr_stats(
         logger.exception("Jellyseerr stats endpoint failed")
         raise HTTPException(status_code=502, detail=f"Jellyseerr fetch failed: {exc}") from exc
     return _serialize(result)
+
+
+@router.get("/requests")
+def get_jellyseerr_requests(
+    jellyfin_service_id: str | None = None,
+    store: SettingsStore = Depends(get_settings_store),
+) -> dict:
+    """Return Jellyseerr requests for the Requests tab table (filter/sort client-side)."""
+    service = resolve_service_record(store, "jellyfin", jellyfin_service_id)
+    if service is None:
+        raise HTTPException(status_code=503, detail="No Jellyfin service is configured.")
+    try:
+        requests = fetch_jellyseer_requests(service)
+    except Exception as exc:  # pragma: no cover - client guards internally
+        logger.exception("Jellyseerr requests endpoint failed")
+        raise HTTPException(status_code=502, detail=f"Jellyseerr fetch failed: {exc}") from exc
+    return {"requests": requests}