Protect upload cleanup and atomic completion paths, add durable media worker leases and brand asset validation, and introduce verified migration/bootstrap/deployment gates.
- 完成白底图 WebP 双轨接口、上传链路与预览缓存改造 - 新增 AI 生图平台成品回传接口、任务状态与表单规则 - 补齐 AI 生成标签、任务详情补全、相关测试与对接文档