feat(admin): art-design-pro integration with local session auth

P1b Task 9: apps/admin based on art-design-pro v3.0.2 (tag, commit
d224dd4; source recorded in apps/admin/SOURCE.md), trimmed to
layout/login/i18n/request/table-form core. Login wired to real
POST /v1/auth/password (single-token session), Bearer header on all
requests, 401 interceptor logout+redirect, request-driven sliding
renewal (refresh at ~80% TTL, single-flight), best-effort
POST /v1/auth/logout on user-menu logout. One protected stub page
(相册管理). Dev port 5176 strictPort + /v1 proxy to 8080. Admin keeps
its own eslint9 flat config; root eslint ignores apps/admin/**.
vitest unit tests for renewal pacing + Playwright e2e (guard redirect,
localized wrong-password error, login lands on stub, token persists
across reload, logout clears session).

Co-Authored-By: Claude Code <noreply@anthropic.com>

apps/admin/src/views/outside/Iframe.vue

@@ -0,0 +1,42 @@
+<template>
+  <div class="box-border w-full h-full" v-loading="isLoading">
+    <iframe
+      ref="iframeRef"
+      :src="iframeUrl"
+      frameborder="0"
+      class="w-full h-full min-h-[calc(100vh-120px)] border-none"
+      @load="handleIframeLoad"
+    ></iframe>
+  </div>
+</template>
+
+<script setup lang="ts">
+  import { IframeRouteManager } from '@/router/core'
+
+  defineOptions({ name: 'IframeView' })
+
+  const route = useRoute()
+  const isLoading = ref(true)
+  const iframeUrl = ref('')
+  const iframeRef = ref<HTMLIFrameElement | null>(null)
+
+  /**
+   * 初始化 iframe URL
+   * 从路由配置中获取对应的外部链接地址
+   */
+  onMounted(() => {
+    const iframeRoute = IframeRouteManager.getInstance().findByPath(route.path)
+
+    if (iframeRoute?.meta) {
+      iframeUrl.value = iframeRoute.meta.link || ''
+    }
+  })
+
+  /**
+   * 处理 iframe 加载完成事件
+   * 隐藏加载状态
+   */
+  const handleIframeLoad = (): void => {
+    isLoading.value = false
+  }
+</script>