fix(admin-service): 将文件存储从本地磁盘改为 MinIO

原实现将 APK/IPA 写入容器内 ./uploads 目录，导致 EACCES 权限错误。
改为通过 MinIO SDK 上传到 oss.gogenex.com / app-releases bucket，
与 docker-compose 中已有的 MINIO_* 环境变量保持一致。

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/services/admin-service/src/application/services/file-storage.service.ts

@@ -1,19 +1,27 @@
 import { Injectable, Logger } from '@nestjs/common';
-import * as fs from 'fs/promises';
-import * as fsSync from 'fs';
-import * as path from 'path';
 import * as crypto from 'crypto';
+import * as path from 'path';
+import { Client as MinioClient } from 'minio';
+import { Readable } from 'stream';
 
 @Injectable()
 export class FileStorageService {
   private readonly logger = new Logger(FileStorageService.name);
-  private readonly uploadDir: string;
+  private readonly minio: MinioClient;
+  private readonly bucket: string;
 
   constructor() {
-    this.uploadDir = process.env.UPLOAD_DIR || './uploads';
+    this.bucket = process.env.MINIO_BUCKET || 'app-releases';
+    this.minio = new MinioClient({
+      endPoint: process.env.MINIO_ENDPOINT || 'localhost',
+      port: parseInt(process.env.MINIO_PORT || '9000', 10),
+      useSSL: process.env.MINIO_USE_SSL === 'true',
+      accessKey: process.env.MINIO_ACCESS_KEY || 'minioadmin',
+      secretKey: process.env.MINIO_SECRET_KEY || 'minioadmin',
+    });
   }
 
-  /** Generate a unique filename for a new upload */
+  /** Generate a unique object key for a new upload */
   generateObjectName(originalName: string, platform: string, versionName: string): string {
     const ext = originalName.split('.').pop() || 'bin';
     const timestamp = Date.now();
@@ -21,20 +29,24 @@ export class FileStorageService {
     return `${platform}-${versionName}-${timestamp}-${random}.${ext}`;
   }
 
-  /** Save file buffer to local disk, return size and sha256 */
-  async saveFile(buffer: Buffer, filename: string): Promise<{ size: number; sha256: string }> {
-    await fs.mkdir(this.uploadDir, { recursive: true });
-    const filePath = path.join(this.uploadDir, filename);
+  /** Upload file buffer to MinIO, return size and sha256 */
+  async saveFile(buffer: Buffer, objectName: string): Promise<{ size: number; sha256: string }> {
     const sha256 = crypto.createHash('sha256').update(buffer).digest('hex');
-    await fs.writeFile(filePath, buffer);
-    this.logger.log(`Saved file: ${filename} (${buffer.length} bytes, sha256: ${sha256})`);
+    const ext = path.extname(objectName).toLowerCase();
+    const contentType = ext === '.apk'
+      ? 'application/vnd.android.package-archive'
+      : 'application/octet-stream';
+
+    await this.minio.putObject(this.bucket, objectName, buffer, buffer.length, {
+      'Content-Type': contentType,
+    });
+    this.logger.log(`Uploaded to MinIO: ${this.bucket}/${objectName} (${buffer.length} bytes)`);
     return { size: buffer.length, sha256 };
   }
 
-  /** Stream local file to a writable (e.g. Express Response) */
-  async streamFile(filename: string, destination: NodeJS.WritableStream): Promise<void> {
-    const filePath = path.join(this.uploadDir, path.basename(filename));
-    const stream = fsSync.createReadStream(filePath);
+  /** Stream a MinIO object to a writable (e.g. Express Response) */
+  async streamFile(objectName: string, destination: NodeJS.WritableStream): Promise<void> {
+    const stream: Readable = await this.minio.getObject(this.bucket, path.basename(objectName));
     await new Promise<void>((resolve, reject) => {
       stream.pipe(destination as any);
       stream.on('end', resolve);
@@ -42,11 +54,10 @@ export class FileStorageService {
     });
   }
 
-  /** Get file size and content-type from local disk */
-  async statFile(filename: string): Promise<{ size: number; contentType: string }> {
-    const filePath = path.join(this.uploadDir, path.basename(filename));
-    const stat = await fs.stat(filePath);
-    const ext = path.extname(filename).toLowerCase();
+  /** Get object size and content-type from MinIO */
+  async statFile(objectName: string): Promise<{ size: number; contentType: string }> {
+    const stat = await this.minio.statObject(this.bucket, path.basename(objectName));
+    const ext = path.extname(objectName).toLowerCase();
     const contentType = ext === '.apk'
       ? 'application/vnd.android.package-archive'
       : 'application/octet-stream';