feat: Phase 0 — monorepo 骨架 + 全表迁移 + FastAPI/Next 骨架 + CI

- uv(workspace) + pnpm monorepo；docker-compose(pg+api+web)
- SQLAlchemy 16 MVP 表 + Alembic 初版迁移(无漂移，users stub)
- FastAPI 骨架：统一错误信封(带 request_id) + structlog + /jobs/:id + OpenAPI
- Next.js 骨架：纸感主题 token + OpenAPI→TS 客户端代码生成(gen:api)
- CI(ruff/mypy/pytest + pg service + alembic 漂移校验)
- 四份设计规格(PRODUCT/UX/ARCHITECTURE/DEV_PLAN) + CLAUDE.md

apps/api/ww_api/routers/health.py

@@ -0,0 +1,17 @@
+"""根路由 + 健康检查。"""
+
+from __future__ import annotations
+
+from fastapi import APIRouter
+
+router = APIRouter()
+
+
+@router.get("/")
+async def root() -> dict[str, str]:
+    return {"service": "ww-api", "status": "ok"}
+
+
+@router.get("/health")
+async def health() -> dict[str, str]:
+    return {"status": "ok"}