权限管理：接入项目级权限矩阵

新增项目级角色权限矩阵，覆盖 PM、CRA、PV、IMP、QA 等项目角色，并通过迁移表持久化各业务模块的读写权限。

后端将参与者、合同费用、物资、启动、里程碑、风险问题、监查稽查、FAQ、共享库、文件版本等接口接入矩阵校验，修复审计日志导出权限和登录 502 的依赖导入问题。

前端新增权限管理页面和项目路由权限映射，按矩阵控制导航显示、直接访问拦截、操作按钮启停，并限制管理后台仅 admin 和授权 PM 可进入。

补充后端权限归一化与接口静态测试、前端路由/权限工具/权限管理页面/工作台等回归测试。

backend/app/api/v1/sites.py

@@ -4,7 +4,7 @@ import json
 from fastapi import APIRouter, Depends, HTTPException, status
 from sqlalchemy.ext.asyncio import AsyncSession
 
-from app.core.deps import get_cra_site_scope, get_current_user, get_db_session, require_study_member, require_study_roles, require_study_not_locked
+from app.core.deps import get_cra_site_scope, get_current_user, get_db_session, require_study_member, require_study_permission, require_study_not_locked
 from app.crud import audit as audit_crud
 from app.crud import site as site_crud
 from app.crud import startup as startup_crud
@@ -26,7 +26,7 @@ async def _ensure_study_exists(db: AsyncSession, study_id: uuid.UUID):
     "/",
     response_model=SiteRead,
     status_code=status.HTTP_201_CREATED,
-    dependencies=[Depends(require_study_roles(["ADMIN", "PM"])), Depends(require_study_not_locked())],
+    dependencies=[Depends(require_study_permission("sites", "write")), Depends(require_study_not_locked())],
 )
 async def create_site(
     study_id: uuid.UUID,
@@ -91,7 +91,7 @@ async def list_sites(
 @router.patch(
     "/{site_id}",
     response_model=SiteRead,
-    dependencies=[Depends(require_study_roles(["ADMIN", "PM"])), Depends(require_study_not_locked())],
+    dependencies=[Depends(require_study_permission("sites", "write")), Depends(require_study_not_locked())],
 )
 async def update_site(
     study_id: uuid.UUID,