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

tests/test_health.py

@@ -0,0 +1,24 @@
+from __future__ import annotations
+
+import httpx
+
+
+async def test_root_returns_ok(client: httpx.AsyncClient) -> None:
+    resp = await client.get("/")
+    assert resp.status_code == 200
+    assert resp.json()["status"] == "ok"
+
+
+async def test_health_endpoint(client: httpx.AsyncClient) -> None:
+    resp = await client.get("/health")
+    assert resp.status_code == 200
+
+
+async def test_response_carries_request_id_header(client: httpx.AsyncClient) -> None:
+    resp = await client.get("/health")
+    assert resp.headers.get("x-request-id")
+
+
+async def test_propagates_incoming_request_id(client: httpx.AsyncClient) -> None:
+    resp = await client.get("/health", headers={"x-request-id": "abc123"})
+    assert resp.headers["x-request-id"] == "abc123"