fix: admin auth UX, password policy, deps, db pool

browser_pool_worker.py

@@ -7,8 +7,26 @@ import threading
 import queue
 import time
 from typing import Callable, Optional, Dict, Any
-import nest_asyncio
-nest_asyncio.apply()
+import nest_asyncio
+
+_NEST_ASYNCIO_APPLIED = False
+_NEST_ASYNCIO_LOCK = threading.Lock()
+
+
+def _apply_nest_asyncio_once() -> None:
+    """按需应用 nest_asyncio，避免 import 时产生全局副作用。"""
+    global _NEST_ASYNCIO_APPLIED
+
+    if _NEST_ASYNCIO_APPLIED:
+        return
+    with _NEST_ASYNCIO_LOCK:
+        if _NEST_ASYNCIO_APPLIED:
+            return
+        try:
+            nest_asyncio.apply()
+        except Exception:
+            pass
+        _NEST_ASYNCIO_APPLIED = True
 
 # 安全修复: 将魔法数字提取为可配置常量
 BROWSER_IDLE_TIMEOUT = int(os.environ.get('BROWSER_IDLE_TIMEOUT', '300'))  # 空闲超时(秒)，默认5分钟
@@ -204,13 +222,15 @@ class BrowserWorkerPool:
         else:
             print(f"[浏览器池] {message}")
 
-    def initialize(self):
-        """初始化工作线程池（按需模式，启动时不创建浏览器）"""
-        with self.lock:
-            if self.initialized:
-                return
-
-            self.log(f"正在初始化工作线程池（{self.pool_size}个worker，按需启动浏览器）...")
+    def initialize(self):
+        """初始化工作线程池（按需模式，启动时不创建浏览器）"""
+        with self.lock:
+            if self.initialized:
+                return
+
+            _apply_nest_asyncio_once()
+
+            self.log(f"正在初始化工作线程池（{self.pool_size}个worker，按需启动浏览器）...")
 
             for i in range(self.pool_size):
                 worker = BrowserWorker(