权限系统迁移完成：接口级权限 + 前置权限检查

## 核心改进
- 完全迁移到接口级权限（68个API端点）
- 实现前置权限检查机制，解决跨模块数据访问权限问题
- 添加权限管理API端点，支持前置权限查询

## 关键变更
1. 权限配置系统
   - 添加OPERATION_PREREQUISITES映射表
   - 所有操作配置前置权限依赖

2. 权限检查函数
   - role_has_api_permission()支持前置权限检查
   - get_missing_prerequisites()获取缺失权限列表

3. 权限管理API
   - GET /api-permissions/operations - 获取所有操作及前置权限
   - GET /api-permissions/operations/prerequisites - 获取前置权限依赖
   - GET /api-permissions/{endpoint_key}/prerequisites - 检查缺失权限

4. API端点迁移
   - 第1批：subjects, visits, aes, monitoring_visit_issues (23个)
   - 第2批：members, sites, project_milestones (11个)
   - 第3批：finance_contracts, fees_contracts, drug_shipments (15个)
   - 第4批：startup endpoints (19个)

## 测试验证
- 单元测试：24个测试全部通过
- 集成测试：22个迁移端点测试通过
- 前置权限测试：12个测试全部通过
- 总计：46个测试全部通过

## 向后兼容性
- 模块级权限表保留用于历史数据
- 接口级权限未配置时自动回退到模块级权限
- 现有权限配置继续有效

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

backend/app/core/project_permissions.py

@@ -8,7 +8,7 @@ from sqlalchemy.ext.asyncio import AsyncSession
 
 from app.models.study_role_permission import StudyRolePermission
 from app.models.api_endpoint_permission import ApiEndpointPermission
-from app.core.api_permissions import API_ENDPOINT_PERMISSIONS, OPERATION_TO_ENDPOINTS
+from app.core.api_permissions import API_ENDPOINT_PERMISSIONS, OPERATION_TO_ENDPOINTS, OPERATION_PREREQUISITES
 from app.core.permission_cache import get_permission_cache
 
 PROJECT_PERMISSION_ROLES = ("ADMIN", "PM", "CRA", "PV", "MEDICAL_REVIEW", "IMP", "QA")
@@ -266,12 +266,14 @@ async def role_has_api_permission(
     study_id: uuid.UUID,
     role: str | None,
     endpoint_key: str,
+    check_prerequisites: bool = True,
 ) -> bool:
     """检查角色是否有权访问特定接口
 
     权限检查优先级：
     1. 接口级权限（如果已配置）
     2. 模块级权限（向后兼容）
+    3. 前置权限检查（如果启用）
     """
     if role == "ADMIN":
         return True
@@ -286,16 +288,53 @@ async def role_has_api_permission(
     )
     perm = result.scalar_one_or_none()
     if perm is not None:
-        return perm.allowed
+        has_main_permission = perm.allowed
+    else:
+        # 2. 如果没有接口级权限，回退到模块级权限（向后兼容）
+        endpoint_config = API_ENDPOINT_PERMISSIONS.get(endpoint_key)
+        if not endpoint_config:
+            return False
 
-    # 2. 如果没有接口级权限，回退到模块级权限（向后兼容）
-    endpoint_config = API_ENDPOINT_PERMISSIONS.get(endpoint_key)
-    if not endpoint_config:
+        module = endpoint_config["module"]
+        action = endpoint_config["action"]
+        has_main_permission = await role_has_project_permission(db, study_id, role, module, action)
+
+    if not has_main_permission:
         return False
 
-    module = endpoint_config["module"]
-    action = endpoint_config["action"]
-    return await role_has_project_permission(db, study_id, role, module, action)
+    # 3. 检查前置权限
+    if check_prerequisites:
+        prerequisites = OPERATION_PREREQUISITES.get(endpoint_key, [])
+        for prereq_endpoint in prerequisites:
+            has_prereq = await role_has_api_permission(
+                db, study_id, role, prereq_endpoint, check_prerequisites=False
+            )
+            if not has_prereq:
+                return False
+
+    return True
+
+
+async def get_missing_prerequisites(
+    db: AsyncSession,
+    study_id: uuid.UUID,
+    role: str | None,
+    endpoint_key: str,
+) -> list[str]:
+    """获取缺失的前置权限列表"""
+    if role == "ADMIN":
+        return []
+
+    missing = []
+    prerequisites = OPERATION_PREREQUISITES.get(endpoint_key, [])
+    for prereq_endpoint in prerequisites:
+        has_prereq = await role_has_api_permission(
+            db, study_id, role, prereq_endpoint, check_prerequisites=False
+        )
+        if not has_prereq:
+            missing.append(prereq_endpoint)
+
+    return missing
 
 
 async def get_api_endpoint_permissions(