feat(apk): 添加最新版本接口并扩展响应数据

- 在现有接口中增加 version 字段返回
- 新增 latest_version 接口用于获取最新APK版本
- 从附件表按创建时间倒序查找最新APK记录
- 统一返回版本号信息到客户端
- 添加暂无安装包的错误处理逻辑

application/api/controller/Apk.php

@@ -104,6 +104,22 @@ class Apk extends Api
         $response = [
             'url' => $this->request->domain() . $attachment->url,
             'filename' => $attachment->filename,
+            'version' => $attachment->extparam,
+        ];
+
+        $this->success('获取成功', $response);
+    }
+
+    public function latest_version(){
+        $attachment = Attachment::where('category', 'apk')
+            ->order('createtime', 'desc')
+            ->find();
+
+        if (!$attachment) {
+            $this->error('暂无安装包');
+        }
+        $response = [
+            'version' => $attachment->extparam,
         ];
 
         $this->success('获取成功', $response);