feat(theme): 接入云海子主题通道（A 类免插件，规范 v1.12 §2/§3）

src/components/layout.vue

@@ -1,5 +1,5 @@
 <script setup lang="ts">
-import { ref, onBeforeMount, onMounted, onUnmounted, watch, computed, inject } from "vue";
+import { ref, onBeforeMount, onMounted, onUnmounted, watch, computed, inject, onBeforeUnmount } from "vue";
 import { useRoute, useRouter } from "vue-router";
 import { Message } from "view-ui-plus";
 import { normalizeModList, flattenMenuNodes } from "@/utils/menuRoute";
@@ -20,6 +20,25 @@ const ssoHost = computed(() => props.layoutData?.ssoHost || "");
 const appName = computed(() => props.layoutData?.appName || "校园公告");
 const appList = computed(() => props.layoutData?.appList || []);
 const userInfo = computed(() => props.layoutData?.userInfo || { name: "管理员", avatar: "" });
+/* 头像：平台键 yh-avatar（yh-theme-init 外观补齐段写入）优先，本仓 userInfo 兜底；
+   监听平台事件重读，不轮询、不手写清理（清键归 init，规范 §3） */
+const yhAvatar = ref("");
+const readYhAvatar = () => {
+    let v: string | null = null;
+    try {
+        v = localStorage.getItem("yh-avatar");
+    } catch {
+        v = null;
+    }
+    yhAvatar.value = v || "";
+};
+onMounted(() => {
+    readYhAvatar();
+    document.addEventListener("yh-appearance-updated", readYhAvatar);
+});
+onBeforeUnmount(() => document.removeEventListener("yh-appearance-updated", readYhAvatar));
+const avatarUrl = computed(() => yhAvatar.value || userInfo.value?.avatar || "");
+
 const isAlone = computed(() => props.layoutData?.isAlone ?? false);
 const modList = computed(() => props.layoutData?.modList || []);
 
@@ -269,7 +288,7 @@ function linkHomePage() {
             <h4 class="fl align-middle">{{ appName }}</h4>
             <div class="school-bg"></div>
             <div class="header-aside fr">
-                <img :src="userInfo.avatar" class="fl align-middle" @click="linkUserInfo" />
+                <img :src="avatarUrl" class="fl align-middle" @click="linkUserInfo" />
                 <a class="name fl align-middle text-ellipsis" href="javascript:void(0);" @click="linkUserInfo">
                     {{ userInfo.name }}
                 </a>