新增 3 个 API 端点:
- POST /tasks/{id}/receive: 确认接收 (PENDING→WIP)
- POST /tasks/{id}/reject: 品质驳回 + 返工闭环
- POST /tasks/{id}/transfer: 完工裂变转交 (多路分支+入库)
数据库迁移 (a1b2c3d4e5f6):
- tasks 表新增 received_at, completed_at, reject_reason, is_rework
- products 表新增 current_location_id
- 数据迁移: 已有任务状态小写→大写 (pending→PENDING 等)
Generic single-database configuration.