feat: 新增多语言文案并修复动态国际化调用问题

1. 新增多语言文件覆盖组件、页面、公共模块的翻译文案
2. 修复多处动态拼接lang key的调用，增加兜底逻辑避免空值或原始key暴露
3. 补全DIY组件、业务页面的国际化适配
4. 新增P2动态key国际化处理方案文档

lang/en-us/member/cancelsuccess.js

@@ -1,3 +1,12 @@
 export const lang = {
 	title: 'Account Cancellation',
+	// member/cancelsuccess.vue page new translation items
+	cancelsuccess: {
+		// You have successfully cancelled your account
+		title: 'You have successfully cancelled your account',
+		// Looking forward to seeing you again. To use again, please re-register
+		desc: 'Looking forward to seeing you again. To use again, please re-register',
+		// Done
+		done: 'Done',
+	},
 }