fix(hub): preserve key monitors when enrich_monitor returns partial payload

Co-authored-by: Cursor <cursoragent@cursor.com>

tests/test_hub_monitor_payload.py

@@ -0,0 +1,39 @@
+"""hub /api/hub/monitor：enrich 局部返回时须保留 keys。"""
+from __future__ import annotations
+
+import sys
+import unittest
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parents[1]
+sys.path.insert(0, str(ROOT))
+
+from hub_bridge import build_hub_monitor_payload  # noqa: E402
+
+
+class TestHubMonitorPayload(unittest.TestCase):
+    def test_partial_enrich_keeps_keys(self):
+        keys = [{"id": 7, "symbol": "BTC/USDT"}]
+        orders = [{"id": 1}]
+        trends = [{"id": 9, "symbol": "ETH/USDT"}]
+        rolls = []
+
+        def enrich_only_trends(**_kw):
+            return {"trends": [{"id": 9, "add_count": 2}]}
+
+        out = build_hub_monitor_payload(
+            keys=keys,
+            orders=orders,
+            trends=trends,
+            rolls=rolls,
+            enrich=enrich_only_trends,
+        )
+        self.assertTrue(out["ok"])
+        self.assertEqual(out["keys"], keys)
+        self.assertEqual(out["orders"], orders)
+        self.assertEqual(out["rolls"], rolls)
+        self.assertEqual(out["trends"][0]["add_count"], 2)
+
+
+if __name__ == "__main__":
+    unittest.main()