feat: add itchat-uos WeChat adapter with QR code login

- Add itchat-uos adapter supporting personal WeChat via QR code login
- Implement message/event converters for text, image, voice, sharing types
- Bridge sync itchat callbacks to async LangBot pipeline via asyncio
- Add QR login API endpoints with session management
- Add frontend QR code login dialog integration
- Fix plugin connector handler attribute check
- Use fresh Core instance per login to avoid singleton state pollution

web/src/i18n/locales/zh-Hans.ts

@@ -1691,6 +1691,15 @@ const zhHans = {
     loginSuccess: '登录成功！令牌已自动填入',
     loginFailed: '登录失败',
   },
+  itchat: {
+    scanLogin: '扫码登录微信',
+    scanQRCode: '请使用微信扫描以下二维码登录',
+    loginSuccess: '登录成功！会话已缓存，保存配置后即可使用',
+    loginFailed: '登录失败',
+    connecting: '正在启动微信登录...',
+    waitingForScan: '等待扫码中',
+    retry: '重试',
+  },
   dingtalk: {
     createApp: '一键创建钉钉应用',
     scanQRCode: '请使用钉钉扫描以下二维码，授权后将自动创建应用并填写凭据',