feat: 持久化 Agent 调用记录

- src/agent: 新增 AgentInvocationRepository，统一封装 Prisma 落库和本地降级存储
- src/agent/agent.service.ts: 创建 Agent 调用后写入数据库，并按项目权限过滤历史列表
- src/agent/agent.module.ts: 注册 Agent 调用记录仓储依赖

src/agent/agent.controller.ts

@@ -26,8 +26,10 @@ export class AgentController {
 
   @Get()
   @ApiOkResponse({ description: '查询 Agent 调用记录。' })
-  listInvocations(): AgentInvocation[] {
-    return this.agentService.listInvocations();
+  async listInvocations(
+    @CurrentUser() user: AuthenticatedUser,
+  ): Promise<AgentInvocation[]> {
+    return this.agentService.listInvocations(user);
   }
 
   @Post()