外观偏好异步补齐C：顶栏 Logo 接平台键 yh-logo-url（服务端学校 Logo 异步生效）

- .logo-badge img 改动态 src：localStorage["yh-logo-url"]（yh-theme-init 异步补齐段写入）优先，本仓 yunhai-logo.svg 兜底，@error 回落兜底——绝无空 src/裂图
- mounted 读一次 + 监听 yh-appearance-updated 即时切换（无需刷新）

src/components/layout.vue

@@ -1,10 +1,11 @@
 <script setup lang="ts">
-import { ref, onBeforeMount, watch, computed } from "vue";
+import { ref, onBeforeMount, onBeforeUnmount, onMounted, watch, computed } from "vue";
 import { useRoute, useRouter } from "vue-router";
 import { Message } from "view-ui-plus";
 import { resolveMenuPage } from "@/utils/menuRoute";
 import ThemeSwitcher from "@/components/ThemeSwitcher.vue";
 import UserAvatar from "@/components/UserAvatar.vue";
+import defaultLogo from "@/assets/image/yunhai-logo.svg";
 
 const props = defineProps<{ layoutData: Record<string, any> }>();
 const route = useRoute();
@@ -24,6 +25,27 @@ const modList = computed(() => props.layoutData?.modList || []);
 
 const pathNavStyle = computed(() => (isAlone.value ? { left: "0", width: "100%" } : null));
 
+// 顶栏 Logo：localStorage["yh-logo-url"]（平台键，yh-theme-init 异步补齐段写入）优先，本仓资产兜底——绝无空 src/裂图。
+// 刷新：mounted 读一次 + 监听 yh-appearance-updated（服务端偏好到达后即时切换，无需刷新页面）。
+const logoUrl = ref<string>(defaultLogo);
+const readLogoUrl = () => {
+    let v: string | null = null;
+    try {
+        v = localStorage.getItem("yh-logo-url");
+    } catch {
+        v = null;
+    }
+    logoUrl.value = v || defaultLogo;
+};
+const onLogoError = () => {
+    if (logoUrl.value !== defaultLogo) logoUrl.value = defaultLogo;
+};
+onMounted(() => {
+    readLogoUrl();
+    document.addEventListener("yh-appearance-updated", readLogoUrl);
+});
+onBeforeUnmount(() => document.removeEventListener("yh-appearance-updated", readLogoUrl));
+
 onBeforeMount(() => {
     routeChange(route);
 });
@@ -159,7 +181,7 @@ function linkHomePage() {
     <div class="layout-wrap">
         <header class="header-container fix">
             <!-- 云海 logo 徽标（结构与 Cms SchoolLayout 对齐，皮肤见通道 base.layout.css .logo-badge） -->
-            <span class="logo-badge fl"><img src="@/assets/image/yunhai-logo.svg" alt="云海" /></span>
+            <span class="logo-badge fl"><img :src="logoUrl" alt="云海" @error="onLogoError" /></span>
             <div class="delimiter fl align-middle"></div>
             <h4 class="fl align-middle">{{ appName }}</h4>
             <div class="school-bg"></div>