refactor: 优化后端支付与微信支付

- 优化payment/config.py、wechat_pay.py
- 优化routers/payment.py、plans.py、quota.py、websocket.py
- 更新main.py、.env.production

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

api/main.py

@@ -109,7 +109,7 @@ async def startup_event():
     
     # 检查并预加载 ASR 模型（在后台线程执行，避免阻塞启动）
     try:
-        from services.asr_service import asr_service
+        from services import asr_service
         asr_ready = await asyncio.to_thread(asr_service.ensure_ready)
         if asr_ready:
             logger.info("ASR 模型已就绪（本地 Whisper）")
@@ -118,6 +118,18 @@ async def startup_event():
     except Exception as e:
         logger.warning(f"ASR 初始化检查失败: {e}")
 
+    # 预初始化微信支付客户端（在后台线程执行，避免首次下单时 _ensure_client 占满 25s 导致超时）
+    try:
+        def _init_wechat_pay_client():
+            from routers.payment import get_payment_service
+            svc = get_payment_service()
+            if svc.is_method_available("wechat"):
+                _ = svc.wechat_client  # 触发 _ensure_client()
+        await asyncio.to_thread(_init_wechat_pay_client)
+        logger.info("微信支付客户端已预初始化")
+    except Exception as e:
+        logger.warning(f"微信支付预初始化失败（首次下单时再初始化）: {e}")
+
 
 @app.on_event("shutdown")
 async def shutdown_event():