fix(mining-admin): 添加 buildNumber 到版本检查返回结果

mining-app VersionInfo.fromJson 要求 buildNumber 字段，
CheckUpdateResult 接口和 checkUpdate 方法之前未包含该字段。

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/services/mining-admin-service/src/application/services/version.service.ts

@@ -62,6 +62,7 @@ export interface CheckUpdateResult {
   latestVersion: {
     versionCode: number
     versionName: string
+    buildNumber: string
     downloadUrl: string
     fileSize: string
     fileSizeFriendly: string
@@ -236,6 +237,7 @@ export class VersionService {
         ? {
             versionCode: latestVersion.versionCode.value,
             versionName: latestVersion.versionName.value,
+            buildNumber: latestVersion.buildNumber.value,
             downloadUrl: latestVersion.downloadUrl.value,
             fileSize: latestVersion.fileSize.bytes.toString(),
             fileSizeFriendly: latestVersion.fileSize.toFriendlyString(),