修复 load_markets 超时后狂打交易所：失败退避 90 秒，避免反复请求导致封 IP。

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

lib/trade/markets_load_guard_lib.py

@@ -0,0 +1,38 @@
+"""交易所 load_markets 失败退避:避免超时后每次调用都狂打 API 导致封 IP."""
+from __future__ import annotations
+
+import time
+from typing import Any, Callable, Optional
+
+
+class MarketsLoadGuard:
+    def __init__(self, *, backoff_sec: float = 60.0, label: str = "markets") -> None:
+        self.loaded = False
+        self.backoff_sec = float(backoff_sec)
+        self.label = label
+        self._fail_until = 0.0
+        self._last_error: Optional[str] = None
+
+    def ensure(self, load_fn: Callable[[], Any], *, force: bool = False) -> None:
+        if self.loaded and not force:
+            return
+        now = time.time()
+        if not force and now < self._fail_until:
+            wait = max(0.0, self._fail_until - now)
+            raise RuntimeError(
+                f"{self.label} load backing off {wait:.0f}s after: {self._last_error or 'previous failure'}"
+            )
+        try:
+            load_fn()
+            self.loaded = True
+            self._fail_until = 0.0
+            self._last_error = None
+        except Exception as e:
+            self.loaded = False
+            self._last_error = str(e)
+            self._fail_until = now + self.backoff_sec
+            print(
+                f"[{self.label}] load_markets failed; backoff {self.backoff_sec:.0f}s: {e}",
+                flush=True,
+            )
+            raise