fix(client): fail closed on polling configuration drift

client/src/cmbuyer_client/ui/settings.py

@@ -5,8 +5,8 @@ from __future__ import annotations
 from pathlib import Path
 from typing import Protocol
 
-from PySide6.QtCore import QRegularExpression, Qt, Signal, Slot
-from PySide6.QtGui import QAction, QKeySequence, QRegularExpressionValidator
+from PySide6.QtCore import Qt, Signal, Slot
+from PySide6.QtGui import QAction, QKeySequence
 from PySide6.QtWidgets import (
     QComboBox,
     QFormLayout,
@@ -77,9 +77,11 @@ class SettingsPage(QScrollArea):
         self.device_token = QLineEdit()
         self.device_token.setObjectName("deviceToken")
         self.device_token.setEchoMode(QLineEdit.EchoMode.Password)
-        self.device_token.setMaxLength(64)
+        # 控件只负责给输入设置合理上限；长度与字符集必须在 save() 中显式
+        # 验证。若这里限制为 64，粘贴 65 位 token 会被 Qt 静默截成合法
+        # 64 位并覆盖原凭据。
+        self.device_token.setMaxLength(256)
         self.device_token.setPlaceholderText("首次必填；已有凭据时留空表示保留")
-        self.device_token.setValidator(QRegularExpressionValidator(QRegularExpression("[0-9a-f]{0,64}"), self))
         form.addRow("设备 token", self.device_token)
 
         self.token_status = QLabel()