fix: normalize all API responses, add error handling and reset confirmation

- Extract normalizeConfig() for consistent response normalization
- Add onError handlers to mutations with useNotify
- Add window.confirm before destructive reset action
- Add resetConfirm translation key to all locales

src/locales/zh.json

@@ -1039,6 +1039,7 @@
       "emojiId": "自定义表情 ID",
       "emojiPlaceholder": "自定义表情 ID（可选）",
       "resetAll": "重置所有样式",
+      "resetConfirm": "将所有按钮样式重置为默认值？",
       "hidden": "已隐藏",
       "customLabels": "按钮名称",
       "labelPlaceholder": "自定义按钮文本",