Add Binance live trading, anti-stuck open/close recovery, and configurable rate limits.

OKX/Binance LIVE share half_open and option_closed_perp_pending repair paths; private REST throttles default to 1s and are tunable in settings.

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

backend/app/sim/ledger.py

@@ -27,15 +27,19 @@ class Ledger:
         kind: str,
         group_id: str | None = None,
         note: str = "",
+        allow_negative: bool = False,
     ) -> float:
-        """amount>0 入账；amount<0 出账。返回余额。"""
+        """amount>0 入账；amount<0 出账。返回余额。
+
+        LIVE 实盘成交后本地账本仅作镜像，须 allow_negative=True，避免「交易所已成交、本地拒记」导致卡仓。
+        """
         now = int(time.time() * 1000)
         with self.db._lock:
             row = self.db._conn.execute("SELECT * FROM ledger_meta WHERE id=1").fetchone()
             assert row is not None
             equity = float(row["equity"]) + float(amount)
             available = float(row["available"]) + float(amount)
-            if available < -1e-9:
+            if not allow_negative and available < -1e-9:
                 raise RuntimeError("可用资金不足")
             self.db._conn.execute(
                 "UPDATE ledger_meta SET equity=?, available=?, updated_at_ms=? WHERE id=1",