feat: T1.5 风险工作台 — 后端 CRUD + 前端风险列表

- 后端：risks 路由（列表/详情/创建/更新/删除）+ 状态流转
- 前端：风险工作台页（卡片列表、状态筛选、内联状态切换、删除）
- 测试：6 个风险 CRUD 测试（总计 43 tests passed）
- 前端构建 13 路由成功

backend/app/main.py

@@ -14,6 +14,7 @@ from app.routers.auth import router as auth_router
 from app.routers.companies import router as companies_router
 from app.routers.dashboard import router as dashboard_router
 from app.routers.reports import router as reports_router
+from app.routers.risks import router as risks_router
 from app.schemas.common import error
 
 
@@ -73,3 +74,4 @@ app.include_router(auth_router, prefix="/api/v1")
 app.include_router(companies_router, prefix="/api/v1")
 app.include_router(reports_router, prefix="/api/v1")
 app.include_router(dashboard_router, prefix="/api/v1")
+app.include_router(risks_router, prefix="/api/v1")