fix: hide empty-state copy on queue credential fail-closed (Closes #458)

When fetch_error is set, render only the unavailable banner and an
explicit not-fetched inventory note. Suppress queue tables, pagination
proof, and "No open items." copy that implied a successful empty fetch.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>

tests/test_webui_queue_dashboard.py

@@ -209,6 +209,37 @@ class TestQueueRoutes(unittest.TestCase):
         self.assertIsNotNone(snapshot.fetch_error)
         self.assertEqual(len(snapshot.prs), 0)
 
+    def test_queue_fail_closed_hides_empty_state_copy(self):
+        with mock.patch("webui.queue_loader.get_auth_header", return_value=None):
+            snapshot = load_queue_snapshot()
+        with mock.patch("webui.app.load_queue_snapshot", return_value=snapshot):
+            response = self.client.get("/queue")
+        self.assertEqual(response.status_code, 200)
+        self.assertIn("Queue unavailable", response.text)
+        self.assertIn("not fetched", response.text.lower())
+        self.assertNotIn("No open items.", response.text)
+        self.assertNotIn("Open pull requests", response.text)
+        self.assertNotIn("pages_fetched", response.text)
+
+    def test_queue_successful_empty_inventory_shows_empty_state(self):
+        def _empty_prs(*_args, **_kwargs):
+            return [], _mock_pagination(0)
+
+        def _empty_issues(*_args, **_kwargs):
+            return [], _mock_pagination(0)
+
+        snapshot = load_queue_snapshot(
+            fetch_prs=_empty_prs,
+            fetch_issues=_empty_issues,
+        )
+        with mock.patch("webui.app.load_queue_snapshot", return_value=snapshot):
+            response = self.client.get("/queue")
+        self.assertEqual(response.status_code, 200)
+        self.assertIsNone(snapshot.fetch_error)
+        self.assertEqual(response.text.count("No open items."), 2)
+        self.assertIn("pages_fetched", response.text)
+        self.assertIn("pagination (complete)", response.text)
+
 
 if __name__ == "__main__":
     unittest.main()