feat: add zero-argument douyin target detection

login_douyin.py

@@ -114,7 +114,10 @@ def main(argv: list[str] | None = None) -> int:
         return 1
 
     print("[INFO] Chrome 已启动。请在打开的浏览器中完成抖音登录和验证码。")
-    print(f"[INFO] 登录完成后执行: ./.venv/bin/python Douyin.py --browser-port {args.browser_port}")
+    next_command = "./.venv/bin/python Douyin.py"
+    if args.browser_port != DEFAULT_BROWSER_PORT:
+        next_command = f"{next_command} --browser-port {args.browser_port}"
+    print(f"[INFO] 登录完成后执行: {next_command}")
     return 0