[CMS-VISUAL] F2: 布局编辑器三栏化——中间 iframe 实时预览（500ms debounce 注入+手动刷新兜底+三档视口）、类型卡 SVG 缩略图（R-40）、展示形态 RadioCard、首用自动编排、序列高度示意（171 测试绿）

src/views/cms/SiteSetting.vue

@@ -120,6 +120,10 @@ const portalPreviewUrl = computed(() =>
             ? portalUrlOf(row.value)
             : ""
 );
+/** F2 实时预览 iframe 地址（编辑模式 = serviceHost + 正式门户首页） */
+const portalFrameUrl = computed(() =>
+    !isCreate.value && row.value ? `${config.serviceHost}${portalUrlOf(row.value)}` : undefined
+);
 
 const rules = {
     code: [
@@ -268,6 +272,7 @@ async function persistTab(tab: TabKey, patch: Record<string, unknown> | null) {
         seeding = true;
         if (tab === "layout") {
             layoutModel.value = lastSavedConfigJson.value;
+            layoutEditorRef.value?.refreshAfterSave?.();
         } else if (tab === "css") {
             customCss.value = readCustomCss(lastSavedConfigJson.value);
         }
@@ -530,7 +535,13 @@ watch(() => store.currentSchool?.schId, () => loadSites());
                             <span class="card-subtitle">首页 = 可编排的区块序列（要闻/栏目文章/画廊/链接组）</span>
                         </div>
                         <div class="card-body">
-                            <HomeLayoutEditor v-model="layoutModel" :site-id="basic.id" ref="layoutEditorRef" @save="saveLayout" />
+                            <HomeLayoutEditor
+                                v-model="layoutModel"
+                                :site-id="basic.id"
+                                :portal-url="portalFrameUrl"
+                                ref="layoutEditorRef"
+                                @save="saveLayout"
+                            />
                         </div>
                         <div class="card-footer">
                             <Button type="primary" :loading="saving.layout" @click="saveLayout">保存首页布局</Button>