清理全局角色残留并修复项目权限判断

frontend/src/views/admin/AuditLogs.vue

@@ -328,7 +328,7 @@ const isAdmin = computed(() => isSystemAdmin(auth.user));
 const projectRole = computed(() => getProjectRole(study.currentStudy, study.currentStudyRole));
 const canProjectExport = computed(() => {
   if (isAdmin.value) return true;
-  return projectRole.value === "PM" && isApiPermissionAllowed(permissionMatrix.value?.[projectRole.value]?.["audit_logs:read"]);
+  return projectRole.value === "PM" && isApiPermissionAllowed(permissionMatrix.value?.[projectRole.value]?.["audit_logs:export"]);
 });
 const canAccessAuditLogs = computed(() => {
   if (isAdmin.value) return true;
@@ -510,6 +510,7 @@ const handleExportCommand = (command: string) => {
 const confirmExport = async (scope: "system" | "project") => {
   const currentStudy = study.currentStudy;
   if (!currentStudy) return;
+  if (scope === "project" && !canProjectExport.value) return;
   const ok = await ElMessageBox.confirm(
     TEXT.modules.adminAuditLogs.exportConfirm,
     TEXT.modules.adminAuditLogs.exportConfirmTitle,