fix: preserve empty native group metadata

tests/test_payload.py

@@ -282,6 +282,7 @@ class Sub2APIQuotaTUITests(unittest.TestCase):
         self.assertEqual(rows["oai-quota-unknown"]["pricing_source"], "-")
         self.assertEqual(rows["oai-quota-ycy-primary"]["pricing_source"], "ycy")
         self.assertEqual(rows["oai-quota-ycy-primary"]["pricing_state"], "error")
+        self.assertIn("error", rows["oai-quota-ycy-primary"]["pricing_fetch"])
         self.assertIsNone(rows["oai-quota-ycy-primary"]["pricing_cny"])
         self.assertEqual(rows["oai-quota-codeplan--primary"]["pricing_source"], "-")
         self.assertEqual(rows["oai-quota-codeplan-primary-"]["pricing_source"], "-")
@@ -342,6 +343,25 @@ class Sub2APIQuotaTUITests(unittest.TestCase):
         self.assertIsNone(failed["pricing_cny"])
         self.assertIn("upstream_error", failed["pricing_fetch"])
 
+    def test_new_projection_does_not_use_key_group_as_native_group_fallback(self) -> None:
+        mod = load_module()
+        rows = mod.normalize_account_rows(
+            {
+                "accounts": [
+                    {
+                        "id": 1,
+                        "name": "ordinary-account",
+                        "routing_group": "key-group",
+                        "account_group_names": [],
+                        "kind": "quota_limited",
+                    }
+                ]
+            }
+        )
+
+        self.assertEqual(rows[0]["routing_group"], "key-group")
+        self.assertEqual(rows[0]["groups"], "-")
+
     def test_normalize_pricing_rows_uses_pricing_monitor_source_balances(self) -> None:
         mod = load_module()
         payload = {