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/tests/test_jellyseerr_stats.py

@@ -117,42 +117,56 @@ def test_stat_widget_unknown_stat_returns_error():
     assert "error" in data
 
 
-def test_jellyseer_client_requests_maps_fields():
-    """requests() paginates /request and maps type/status/media_status enums."""
+def test_jellyseer_client_open_requests_resolves_titles():
+    """open_requests() fetches pending+approved via filter and resolves titles."""
     from media_library_viewer_api.clients.jellyseerr import JellyseerrClient
 
     c = JellyseerrClient("https://js.example.com", "key")
     c.session = MagicMock()
-    resp = MagicMock()
-    resp.raise_for_status.return_value = None
-    resp.status_code = 200
-    resp.text = ""
-    resp.json.return_value = {
-        "results": [
-            {
-                "id": 7,
-                "type": 1,
-                "title": "Inception",
-                "status": 1,
-                "media": {"status": 5},
-                "createdAt": 1_700_000_000,
-            }
-        ]
-    }
-    c.session.get.return_value = resp
 
-    out = c.requests(500)
+    def mock_get(url, **kw):
+        resp = MagicMock()
+        resp.raise_for_status.return_value = None
+        resp.status_code = 200
+        resp.text = ""
+        params = kw.get("params", {})
+        if "/movie/" in url or "/tv/" in url:
+            resp.json.return_value = {"title": "Inception"}  # title resolution
+        elif params.get("filter") == "pending":
+            resp.json.return_value = {
+                "results": [
+                    {
+                        "id": 7,
+                        "type": 1,
+                        "status": 1,
+                        "media": {"tmdbId": 123, "status": 5},
+                        "createdAt": 1_700_000_000,
+                    }
+                ]
+            }
+        else:
+            resp.json.return_value = {"results": []}
+        return resp
+
+    c.session.get.side_effect = mock_get
+
+    out = c.open_requests()
 
     assert len(out) == 1
     r = out[0]
     assert r["id"] == 7
-    assert r["type"] == "movie"  # 1 -> movie
-    assert r["name"] == "Inception"
-    assert r["status"] == "pending"  # 1 -> pending
-    assert r["media_status"] == "available"  # 5 -> available
+    assert r["type"] == "movie"
+    assert r["name"] == "Inception"  # resolved via /movie/123
+    assert r["status"] == "pending"
+    assert r["media_status"] == "available"
     assert r["created_at"] == 1_700_000_000
-    # Single short page -> no second fetch.
-    assert c.session.get.call_count == 1
+
+    # Title is cached: a second call doesn't re-fetch /movie/123.
+    movie_calls_before = sum(1 for call in c.session.get.call_args_list if "/movie/" in call.args[0])
+    assert movie_calls_before == 1
+    c.open_requests()  # second poll
+    movie_calls_after = sum(1 for call in c.session.get.call_args_list if "/movie/" in call.args[0])
+    assert movie_calls_after == 1  # cached, no new /movie call
 
 
 def test_fetch_jellyseer_requests_not_configured_returns_empty():