refactor(commodity-detail): optimize performance and fix UI flicker issues

1. add empty form tip for product message section
2. lazy load goods form to unblock initial page render
3. optimize category and tabbar rendering to fix flicker on WeChat mini-program
4. delay non-critical data processing to improve first-screen rendering speed
5. fix popup blank issue when opening product message form for the first time

lang/zh-cn/goods/detail.js

@@ -108,6 +108,7 @@ export const lang = {
 
 	// 商品留言
 	productMessage: '商品留言',
+	formEmptyTip: '暂无需填写的留言字段',
 
 	// 智能客服
 	aiCustomerService: '智能客服',