feat(前端UI): 实现运维监控前端界面

- 新增帮助提示组件（HelpTooltip.vue）
- 更新侧边栏添加 ops 监控菜单项
- 扩展设置视图集成 ops 配置面板
- 新增 ops 监控视图目录（dashboard, alerts, realtime, settings 等）

frontend/src/components/common/HelpTooltip.vue

@@ -0,0 +1,44 @@
+<script setup lang="ts">
+import { ref } from 'vue'
+
+defineProps<{
+  content?: string
+}>()
+
+const show = ref(false)
+</script>
+
+<template>
+  <div
+    class="group relative ml-1 inline-flex items-center align-middle"
+    @mouseenter="show = true"
+    @mouseleave="show = false"
+  >
+    <!-- Trigger Icon -->
+    <slot name="trigger">
+      <svg
+        class="h-4 w-4 cursor-help text-gray-400 transition-colors hover:text-primary-600 dark:text-gray-500 dark:hover:text-primary-400"
+        fill="none"
+        viewBox="0 0 24 24"
+        stroke="currentColor"
+        stroke-width="2"
+      >
+        <path
+          stroke-linecap="round"
+          stroke-linejoin="round"
+          d="M13 16h-1v-4h-1m1-4h.01M21 12a9 9 0 11-18 0 9 9 0 0118 0z"
+        />
+      </svg>
+    </slot>
+
+    <!-- Popover Content -->
+    <div
+      v-show="show"
+      class="absolute bottom-full left-1/2 z-50 mb-2 w-64 -translate-x-1/2 rounded-lg bg-gray-900 p-3 text-xs leading-relaxed text-white shadow-xl ring-1 ring-white/10 opacity-0 transition-opacity duration-200 group-hover:opacity-100 dark:bg-gray-800"
+    >
+      <slot>{{ content }}</slot>
+      <div class="absolute -bottom-1 left-1/2 h-2 w-2 -translate-x-1/2 rotate-45 bg-gray-900 dark:bg-gray-800"></div>
+    </div>
+  </div>
+</template>
+