fix: prevent browser process leaks and improve robustness

- fix(browser): wrap context lifecycle in try/finally to ensure browser
  closes on exceptions and KeyboardInterrupt (login, sniffer, generator)
- fix(browser): replace time.sleep with Playwright native waits
  (wait_for, wait_for_timeout) for more reliable element interaction
- fix(browser): use parameterized page.evaluate instead of f-string
  JS injection in generator polling
- fix(api): add retry logic in wait_for_completion to survive transient
  network errors
- fix(config): add prepare_profile_dir to copy profile to temp dir,
  preventing Chromium SingletonLock conflicts when tools run concurrently
- fix(sniffer): stream API logs to tempfile instead of unbounded memory
  list to avoid OOM
- fix(api): specify encoding='utf-8' when loading cookies from file

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

hunyuan3dweb/api_complete.py

@@ -411,7 +411,7 @@ from .config import get_cookie_path
 def load_cookies_from_file(filepath: Optional[str] = None) -> str:
     """从文件加载Cookie，默认读取用户配置目录的 cookies.txt"""
     path = filepath or str(get_cookie_path())
-    with open(path, 'r') as f:
+    with open(path, 'r', encoding='utf-8') as f:
         return f.read().strip()