ci: 修复 Standalone 与 Mock 依赖检查路由

[a3384379]

目的

修复 PR #116 合并后复审确认的三个 CI 路由边界：

• backend/app/core/standalone_schema.py 作为独立 SQLite 初始化和升级入口，要求 backend-full 与 Windows/Standalone 验证；不机械要求 PostgreSQL V2→V3 演练。
• Mock 镜像实际安装的 mock-target/pyproject.toml 与 mock-target/uv.lock 变更要求 Compose 与 Security；Docker 构建改用 uv sync --locked，拒绝清单与锁文件不一致。
• backend/app/schemas/ 的 API 请求/响应模型继续要求后端、前端消费者与 Compose 验证，但不再仅凭目录名要求历史数据库升级和 Windows 打包；迁移、模型、仓储路径保持既有升级要求。

验证

• 修改前新增路由回归：9 个预期失败，确认三处缺口。
• make test-backend-targeted TARGETS='["tests/test_ci_plan.py","tests/test_standalone_runtime.py"]'：90 passed，包含现存 SQLite 升级后的旧数据读取与后续写入测试。
• uv run pytest --no-cov tests/test_ci_plan.py tests/test_required_gate.py：105 passed。
• Ruff format/check（路由脚本与测试）和 git diff --check：通过。
• 当前 Mock 项目的两次 uv sync --locked --dry-run：通过；临时加入未锁定依赖时，--frozen 返回成功而 --locked 明确拒绝。

本 PR 修改 CI 治理文件，需使用受控 Bootstrap 验收。上述本地测试不代表远端检查已通过。

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📝 Code Review	✅ Completed 2026-09-27T13:05:24.542904Z	99defa3	PR opened

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