fix(登录页): 修正验证码校验规则为4位数字

修复登录页验证码校验逻辑，将验证码长度从4-6位改为严格4位数字

 <!--
  * @Date: 2025-11-10 18:08:59
  * @LastEditors: hookehuyr hookehuyr@gmail.com
- * @LastEditTime: 2025-11-11 14:01:40
+ * @LastEditTime: 2025-11-11 15:51:10
  * @FilePath: /stdj_h5/src/views/Login.vue
  * @Description: 登录页
 -->
@@ -45,7 +45,7 @@
 </template>
 
 <script setup>
-import { ref, onUnmounted, computed } from 'vue'
+import { ref, onUnmounted, computed, onMounted } from 'vue'
 import { useRoute, useRouter } from 'vue-router'
 import { useTitle } from '@vueuse/core'
 import { smsAPI } from '@/api/common.js'
@@ -82,7 +82,7 @@ const login_disabled = computed(function () {
   return (
     logging.value ||
     !is_valid_phone(phone.value) ||
-        !/^\d{4,6}$/.test(String(code.value || '').trim())
+    !/^\d{4}$/.test(String(code.value || '').trim())
   )
 })
 
@@ -172,8 +172,8 @@ const on_login = async function () {
     showFailToast('请输入有效的手机号')
     return
   }
-    if (!/^\d{4,6}$/.test(String(code.value || '').trim())) {
-        showFailToast('请输入4~6位数字验证码')
+  if (!/^\d{4}$/.test(String(code.value || '').trim())) {
+    showFailToast('请输入4位数字验证码')
     return
   }
   try {
@@ -193,6 +193,9 @@ const on_login = async function () {
   }
 }
 
+onMounted(() => {
+})
+
 // 组件卸载时清理计时器
 onUnmounted(function () {
   if (timer_id.value) {
@@ -220,6 +223,7 @@ onUnmounted(function () {
 .logo-title {
   margin-bottom: 2rem;
 }
+
 .logo-img {
   height: 5.5rem;
   object-fit: contain;
@@ -234,6 +238,7 @@ onUnmounted(function () {
   padding: 1rem;
   box-shadow: 0 0.25rem 1rem rgba(0, 0, 0, 0.06);
 }
+
 .card-title {
   text-align: center;
   color: #432C0E;
@@ -248,6 +253,7 @@ onUnmounted(function () {
   margin-top: 1.25rem;
   margin-bottom: 0.75rem;
 }
+
 .code-row {
   display: flex;
   gap: 0.5rem;
@@ -258,6 +264,7 @@ onUnmounted(function () {
 .input-with-icon {
   position: relative;
 }
+
 .input-with-icon::before {
   content: '';
   position: absolute;
@@ -270,9 +277,11 @@ onUnmounted(function () {
   background-repeat: no-repeat;
   transform: translateY(-50%);
 }
+
 .input-with-icon.phone::before {
   background-image: url('https://cdn.ipadbiz.cn/stdj/images/%E6%89%8B%E6%9C%BA@2x.png');
 }
+
 .input-with-icon.code::before {
   background-image: url('https://cdn.ipadbiz.cn/stdj/images/%E9%AA%8C%E8%AF%81%E7%A0%81@2x-1.png');
 }
@@ -286,6 +295,7 @@ onUnmounted(function () {
   padding: 0 0.75rem 0 2.25rem; // 为左侧图标预留空间
   box-shadow: inset 0 0 0 0.0625rem rgba(0, 0, 0, 0.08);
 }
+
 .input::placeholder {
   color: #999999;
 }
@@ -302,12 +312,15 @@ onUnmounted(function () {
   text-align: center;
   line-height: 2.5rem;
 }
+
 .btn.send {
   white-space: nowrap;
 }
+
 .btn.primary {
   width: 100%;
 }
+
 .btn.disabled {
   // 不可操作态：明显的灰显与禁止样式
   opacity: 0.5;