feat(auth): print a scannable ASCII QR in the terminal

WSL and --no-browser never showed the PNG, and placeholder Chinese cookies crashed urllib latin-1 headers before the code was issued.

reaction_board/cli.py

@@ -99,7 +99,7 @@ def _build_parser() -> argparse.ArgumentParser:
     auth = sub.add_parser("auth", parents=[common], help="扫码授权并更新指定账号 Cookie")
     auth.add_argument("--account", choices=("read", "write"), default="read",
                       help="要授权的账号角色（默认 read）")
-    auth.add_argument("--no-browser", action="store_true", help="不自动打开二维码图片")
+    auth.add_argument("--no-browser", action="store_true", help="不自动打开二维码图片（仍在终端打印 ASCII 二维码）")
     auth.add_argument("--timeout", type=int, default=180, metavar="SEC",
                       help="等待扫码的超时时间（默认 180 秒）")
     auth_check = sub.add_parser("auth-check", parents=[common], help="检查账号登录态")