📝 docs(wechat-auth): update environment variable configuration instructions

- remove WECHAT_MP_REDIRECT_URI from sample configuration as it's no longer required for basic setup

.roo/commands/wechat-auth-微信服务号网页授权登录开发.md

@@ -456,7 +456,6 @@ import { toast } from 'sonner'
 # 微信服务号配置（公众号）
 WECHAT_MP_APP_ID=your_wechat_mp_app_id
 WECHAT_MP_APP_SECRET=your_wechat_mp_app_secret
-WECHAT_MP_REDIRECT_URI=https://yourdomain.com/auth/wechat/mp/callback
 
 # 微信开放平台配置（可选，用于多端统一）
 WECHAT_OPEN_APP_ID=your_wechat_open_app_id