chore(mining-admin-service): 统一API版本为v2

- 将globalPrefix从api/v1改为api/v2
- 更新Swagger文档版本为2.0

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

backend/services/mining-admin-service/src/main.ts

@@ -8,12 +8,12 @@ async function bootstrap() {
 
   app.useGlobalPipes(new ValidationPipe({ whitelist: true, transform: true, forbidNonWhitelisted: true }));
   app.enableCors({ origin: process.env.CORS_ORIGIN || '*', credentials: true });
-  app.setGlobalPrefix('api/v1');
+  app.setGlobalPrefix('api/v2');
 
   const config = new DocumentBuilder()
     .setTitle('Mining Admin Service API')
     .setDescription('挖矿管理后台 API 文档')
-    .setVersion('1.0')
+    .setVersion('2.0')
     .addBearerAuth()
     .addTag('Auth', '认证')
     .addTag('Config', '配置管理')