feat(frontend): 实现仪表盘和子系统导航

页面：
- views/dashboard/Index.vue，首页仪表盘（资源大盘、集群拓扑、最近任务）
- views/subsystem/Navigation.vue，子系统导航页（6 个卡片网格展示）

组件：
- components/SubsystemCard.vue，子系统卡片组件（图标、名称、状态、SSO 跳转）

API：
- api/subsystem.ts，子系统相关接口（获取列表、SSO URL）

子系统：Wayne、CloudDM、CacheCloud、Apollo、qpass、Grafana

frontend/src/views/subsystem/Navigation.vue

@@ -0,0 +1,58 @@
+<template>
+  <div>
+    <div class="page-head">
+      <div>
+        <h1>子系统导航</h1>
+        <p>统一 LDAP 账号，点击即用免二次登录（同账号同密码）</p>
+      </div>
+    </div>
+    <div class="ext-grid">
+      <SubsystemCard
+        v-for="system in subsystems"
+        :key="system.id"
+        :system="system"
+      />
+    </div>
+  </div>
+</template>
+
+<script setup lang="ts">
+import { ref, onMounted } from 'vue'
+import { subsystemApi, type Subsystem } from '@/api/subsystem'
+import SubsystemCard from '@/components/SubsystemCard.vue'
+
+const subsystems = ref<Subsystem[]>([])
+
+onMounted(async () => {
+  const { data } = await subsystemApi.getSubsystems()
+  subsystems.value = data
+})
+</script>
+
+<style scoped>
+.page-head {
+  display: flex;
+  align-items: flex-end;
+  justify-content: space-between;
+  margin-bottom: 18px;
+}
+
+.page-head h1 {
+  font-size: 19px;
+  margin: 0 0 4px;
+  font-weight: 700;
+  letter-spacing: 0.2px;
+}
+
+.page-head p {
+  margin: 0;
+  color: var(--text-dim);
+  font-size: 12.5px;
+}
+
+.ext-grid {
+  display: grid;
+  grid-template-columns: repeat(3, 1fr);
+  gap: 14px;
+}
+</style>