add backend skeleton

[xiaocheny214]

背景

添加后端骨架

内容

    
backend/                          # uv workspace 根
  pyproject.toml                   # workspace 定义 + 根依赖
  packages/
    common/                        # 独立包 · 共享内核(无内部依赖)
      src/windup_common/
        enums/  exceptions/  constants/  utils/
        models/        # 跨层契约 DTO/VO (pydantic)
        result/        # 统一返回 / 分页包装

    framework/                     # 独立包 · 基础设施  -> 依赖 common
      src/windup_framework/
        config/        # pydantic-settings
        db/            # SQLAlchemy engine/session/Base (postgres)
        mq/            # RocketMQ producer/consumer 封装
        storage/       # 对象存储客户端 (MinIO/OSS/S3)
        httpx_client/  # 外部 HTTP 客户端
        search/        # 外部检索客户端(SERPAPI 等)
        auth/          # JWT / 租户鉴权
        providers/     # AI 模型底层适配器(文本/图像/视频/embedding/抠图) behind interfaces
        logging/

    ai_engine/                     # 独立包 · 资产生产引擎  -> 依赖 common+framework,暴露 ports
      src/windup_ai_engine/
        ports/         # 对外接口 + callback ports(server/framework 实现,注入)
        graph/         # langgraph 图:节点 / 边 / 条件路由 / 反射 / 规划
        strategy/      # DerivationStrategy: SpriteSheetStrategy / VideoFrameStrategy
        postprocess/   # 抠图 / 背景去除 / 调色
        slicing/       # 精灵图集切帧、按动作×方向组织
        prompt/        # prompt 模板结构 + 渲染(运行时变量由入参注入)
        impl/          # CharacterGenerator 实现:装配 graph + ports,跑图

    app/                           # 应用包  -> 依赖 common/framework/ai_engine
      src/windup_app/
        server/        # 业务领域:租户 / 角色 / 生成任务 / 资产 / 样本 / 配额
          tenant/  character/  generation/  asset/  sample/  quota/
        web/           # FastAPI 表现层
          api/         # routers
          schemas/     # 请求/响应 schema(面向前端)
          middleware/  # 鉴权 / 租户上下文 / 异常处理
          sse/         # SSE/WS 进度推送
        worker/        # RocketMQ 消费入口
        bootstrap/     # 装配:create_app、依赖注入、路由挂载、port 实现绑定
  tests/

变更范围

• 新增后端骨架包含代码部分

[gemini-code-assist]

Caution

The consumer version of Gemini Code Assist on GitHub has been sunset. All code review activity has officially ceased.

[fennoai]

No high-confidence issues found in the current PR diff.

Validation: git diff --check and Python bytecode compilation passed. pytest/uv could not be run because neither tool is installed in the review environment.