fix: 登录页导航栏显示"登录"替代uni-app，按钮改为一键登录并居中

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

charge-front/src/pages.json

@@ -19,7 +19,8 @@
     {
       "path": "pages/login/login",
       "style": {
-        "navigationStyle": "default"
+        "navigationStyle": "default",
+        "navigationBarTitleText": "登录"
       }
     }
   ],

charge-front/src/pages/login/login.vue

@@ -13,7 +13,7 @@
         :disabled="submitting"
         @getphonenumber="handleLogin"
       >
-        微信手机号一键登录
+        一键登录
       </button>
 
       <text v-if="errorMsg" class="err">{{ errorMsg }}</text>
@@ -105,14 +105,15 @@ const performRedirect = (url: string) => {
 .btn {
   width: 100%;
   height: 100rpx;
+  display: flex;
+  align-items: center;
+  justify-content: center;
   background: var(--color-primary);
   color: #fff;
   font-size: 32rpx;
   font-weight: 600;
   border-radius: 50rpx;
-  line-height: 100rpx;
   border: none;
-  letter-spacing: 2rpx;
 }
 
 .btn::after {