feat(backend): Phase 0 项目骨架完成 — 后端/前端/数据库/Docker

- 后端：FastAPI + SQLAlchemy + Alembic，7 张核心表迁移成功
- 前端：Next.js 16 + TailwindCSS 4 + 三端布局（投资人/创始人/Admin）
- 数据库：PostgreSQL 16，7 张核心实体表（tenants/users/companies/monthly_reports/health_scores/risk_events/audit_logs）
- Docker：docker-compose.yml + 前后端 Dockerfile
- 测试：健康检查 4 个测试全部 GREEN
- 文档：README/run.md/AGENTS.md/docs 体系完整

backend/tests/__init__.py

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+"""测试包。"""

backend/tests/test_health.py

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+"""健康检查端点测试。"""
+
+import pytest
+from fastapi.testclient import TestClient
+
+from app.main import app
+
+
+@pytest.fixture
+def client():
+    """创建测试客户端。"""
+    return TestClient(app)
+
+
+class TestHealthCheck:
+    """健康检查测试。"""
+
+    def test_health_returns_ok(self, client: TestClient):
+        """RED: 健康检查应返回 200 和 status=ok。"""
+        response = client.get("/health")
+        assert response.status_code == 200
+        data = response.json()
+        assert data["status"] == "ok"
+        assert data["service"] == "aiportpilot-backend"
+
+    def test_health_returns_version(self, client: TestClient):
+        """RED: 健康检查应返回版本号。"""
+        response = client.get("/health")
+        data = response.json()
+        assert "version" in data
+
+    def test_trace_id_in_response_header(self, client: TestClient):
+        """RED: 响应头应包含 X-Trace-Id。"""
+        response = client.get("/health")
+        assert "X-Trace-Id" in response.headers
+
+    def test_trace_id_echoed_from_request(self, client: TestClient):
+        """RED: 请求头传入的 trace_id 应在响应头中原样返回。"""
+        custom_trace_id = "test-trace-12345"
+        response = client.get("/health", headers={"X-Trace-Id": custom_trace_id})
+        assert response.headers["X-Trace-Id"] == custom_trace_id