feat: add per-button enable/disable toggle and custom labels per locale

- Add Toggle per section card to show/hide button in main menu
- Add collapsible locale label inputs (ru, en, ua, zh, fa) per section
- Normalize server response for backward compatibility with older API
- Update all 4 locale files with new translation keys

src/locales/zh.json

@@ -1039,6 +1039,10 @@
       "emojiId": "自定义表情 ID",
       "emojiPlaceholder": "自定义表情 ID（可选）",
       "resetAll": "重置所有样式",
+      "hidden": "已隐藏",
+      "customLabels": "按钮名称",
+      "labelPlaceholder": "自定义按钮文本",
+      "labelsHint": "留空 = 默认名称",
       "sections": {
         "home": "主页",
         "subscription": "订阅",