feat: 封装一些函数，补充页面样式

Co-authored-by: Copilot <copilot@github.com>

app/components/HeaderCom.vue

@@ -0,0 +1,25 @@
+<script setup lang="ts">
+import { useUserStore } from "~/stores";
+import logo from "~/assets/logo.png";
+
+const userStore = useUserStore();
+const { isOnline } = storeToRefs(userStore);
+</script>
+
+<template>
+  <div class="w-full h-16 flex items-center justify-between border-b px-4">
+    <img
+      :src="logo"
+      alt="AI Art Studio logo"
+      class="h-8 select-none"
+      :class="{
+        'cursor-pointer': $route.path !== '/'
+      }"
+      @click="$router.push('/')"
+    />
+    <div v-if="!$route.path.includes('login')">
+      <el-button v-if="isOnline" @click="userStore.logout()">退出</el-button>
+      <el-button v-else @click="$router.push('/login')">登录</el-button>
+    </div>
+  </div>
+</template>