fix(backup-service): 修正启动路径和健康检查等待时间

- start-period: 5s -> 40s (给予足够启动时间)
- CMD: dist/main.js -> dist/src/main.js (修正实际路径)
- 保持使用 wget (Alpine 原生支持)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

backend/services/backup-service/Dockerfile

@@ -49,8 +49,8 @@ USER nestjs
 EXPOSE 3002
 
 # Health check
-HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3 \
+HEALTHCHECK --interval=30s --timeout=3s --start-period=40s --retries=3 \
     CMD wget --no-verbose --tries=1 --spider http://localhost:3002/health || exit 1
 
 # Start the application
-CMD ["node", "dist/main.js"]
+CMD ["node", "dist/src/main.js"]