Speed up CTP account display: refresh equity on fast snapshot without waiting for full position sync.

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

modules/core/trading_context.py

@@ -88,8 +88,14 @@ def _cached_ctp_account(mode: str) -> dict[str, float]:
 
         snap = position_hub.get_snapshot() or {}
         cap = float(snap.get("capital") or 0)
-        if cap > 0:
-            return {"balance": cap}
+        avail = snap.get("account_available")
+        if cap > 0 or avail is not None:
+            out: dict[str, float] = {}
+            if cap > 0:
+                out["balance"] = cap
+            if avail is not None:
+                out["available"] = float(avail)
+            return out
     except Exception:
         pass
     try: