docs(design): 删除磁盘监控设计文档并更新前端页面结构规范

- 删除 frontend/src/views/systemMonitor/2026-04-22-disk-monitor-design.md 设计文档
- 删除 frontend/src/views/tools/addLedger/API_DEBUG.md 调试文档
- 在 AGENTS.md 中新增前端页面结构归档章节，规范复杂工具页结构
- 明确 index.vue、components/、utils/ 职责边界和拆分原则
- 规定页面级类型和 contract 脚本管理方式
- 统一复杂页面拆分优先顺序和注意事项

frontend/src/layouts/components/Tabs/index.vue

@@ -57,7 +57,7 @@ onMounted(() => {
 
 const ensureParentTab = () => {
     const parentPath = resolveCurrentTabPath()
-    if (!parentPath || tabStore.tabsMenuList.some(item => item.path === parentPath)) return
+    if (!parentPath) return
 
     const parentRoute = router.getRoutes().find(item => item.path === parentPath && item.name)
     if (!parentRoute) return
@@ -69,7 +69,8 @@ const ensureParentTab = () => {
         path: parentRoute.path,
         name: parentRoute.name as string,
         close: !parentRoute.meta.isAffix,
-        isKeepAlive: parentRoute.meta.isKeepAlive as boolean
+        isKeepAlive: (route.meta.isKeepAlive ?? parentRoute.meta.isKeepAlive) as boolean,
+        cacheName: (route.meta.cacheName || parentRoute.meta.cacheName) as string | undefined
     })
 }
 
@@ -87,6 +88,7 @@ watch(
                 title: route.meta.title as string,
                 path: route.fullPath,
                 name: route.name as string,
+                cacheName: route.meta.cacheName as string | undefined,
                 close: !route.meta.isAffix,
                 isKeepAlive: route.meta.isKeepAlive as boolean
             }
@@ -113,6 +115,7 @@ const initTabs = () => {
             title: item.meta.title as string,
             path: item.path,
             name: item.name as string,
+            cacheName: item.meta.cacheName as string | undefined,
             close: !item.meta.isAffix,
             isKeepAlive: item.meta.isKeepAlive as boolean,
             unshift: true