feat(users): add version checking endpoint

Add app version checking functionality to notify users when updates are available. The feature extracts the current version from the x-App-Version header, compares it with the latest configured version, and returns update information including download links and release notes.

src/common/decorators/app-version.decorator.ts

@@ -0,0 +1,12 @@
+import { createParamDecorator, ExecutionContext } from '@nestjs/common';
+
+/**
+ * 从请求头中获取应用版本号的装饰器
+ * 从 x-App-Version 请求头中提取版本信息
+ */
+export const AppVersion = createParamDecorator(
+  (data: unknown, ctx: ExecutionContext): string | undefined => {
+    const request = ctx.switchToHttp().getRequest();
+    return request.headers['x-app-version'];
+  },
+);