feat(hub): background board poll every 5s with SSE snapshot updates

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

tests/test_hub_board_store.py

@@ -0,0 +1,44 @@
+"""后台 board 缓存：版本递增与快照。"""
+from __future__ import annotations
+
+import asyncio
+import sys
+import unittest
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parents[1]
+sys.path.insert(0, str(ROOT))
+sys.path.insert(0, str(ROOT / "manual_trading_hub"))
+
+from hub_board_cache import MonitorBoardStore  # noqa: E402
+
+
+class TestHubBoardStore(unittest.TestCase):
+    def test_snapshot_and_version(self) -> None:
+        store = MonitorBoardStore()
+        store.version = 2
+        store.payload = {"ok": True, "rows": [{"id": "0"}], "updated_at": "2026-01-01T00:00:00"}
+        snap = store.snapshot_dict()
+        self.assertEqual(snap["board_version"], 2)
+        self.assertEqual(len(snap["rows"]), 1)
+
+    def test_aggregate_increments_version(self) -> None:
+        async def run() -> None:
+            store = MonitorBoardStore()
+            n = 0
+
+            async def build():
+                nonlocal n
+                n += 1
+                return {"ok": True, "rows": [{"n": n}], "updated_at": "t"}
+
+            await store.start(build)
+            await asyncio.sleep(0.05)
+            self.assertGreaterEqual(store.version, 1)
+            await store.stop()
+
+        asyncio.run(run())
+
+
+if __name__ == "__main__":
+    unittest.main()