feat: 添加后退按钮组件并更新认证路由和视图

src/views/auth/signup.vue

@@ -0,0 +1,22 @@
+<script lang='ts' setup>
+
+</script>
+
+<template>
+  <ion-page>
+    <ion-header>
+      <ion-toolbar class="ion-toolbar">
+        <back-button slot="start" />
+        <ion-title>登录</ion-title>
+      </ion-toolbar>
+    </ion-header>
+
+    <ion-content :fullscreen="true" class="ion-padding">
+      <div class="max-w-md mx-auto flex flex-col gap-6">
+        <!-- 登录表单内容省略 -->
+      </div>
+    </ion-content>
+  </ion-page>
+</template>
+
+<style lang='css' scoped></style>