feat: 更新 API 地址，优化样式和组件，添加新主题变量

src/views/onchain-address/index.vue

@@ -9,7 +9,7 @@ const { user } = useAuth();
     <IonHeader>
       <IonToolbar class="ui-toolbar">
         <ion-buttons slot="start">
-          <ion-back-button default-href="/layout/user" />
+          <ion-back-button />
         </ion-buttons>
         <ion-title>My Onchain Address</ion-title>
       </IonToolbar>
@@ -19,7 +19,7 @@ const { user } = useAuth();
         <div class="container">
           <div class="user-info">
             <div class="avatar-wrapper">
-              <ion-avatar class="avatar">
+              <ion-avatar class="avatar size-16">
                 <img alt="User avatar" :src="user?.image || 'https://fuss10.elemecdn.com/a/3f/3302e58f9a181d2509f3dc0fa68b0jpeg.jpeg'">
               </ion-avatar>
             </div>