fix(admin): 启动 Loading 使用中性 Loading... 文案

避免刷新时展示构建期品牌名 DaxPay Admin；初始 title 同步为 Loading...，
进站后仍由站点配置 systemName 覆盖，无需 i18n。

apps/daxpay-admin/index.html

@@ -11,8 +11,8 @@
       name="viewport"
       content="width=device-width,initial-scale=1.0,minimum-scale=1.0,maximum-scale=1.0,user-scalable=0"
     />
-    <!-- 由 vite 注入 VITE_APP_TITLE 变量，在 .env 文件内配置 -->
-    <title><%= VITE_APP_TITLE %></title>
+    <!-- 初始中性标题: 避免绑定构建期品牌名; 进站后由 bootstrap watchEffect 用站点配置 systemName 覆盖 -->
+    <title>Loading...</title>
     <!-- id 固定, 由 init-website-config 受控更新; 禁止空 href -->
     <link id="favicon" rel="icon" href="/favicon.ico" />
     <script>

apps/daxpay-admin/loading.html

@@ -0,0 +1,114 @@
+<style data-app-loading="inject-css">
+  html {
+    /* same as ant-design-vue/dist/reset.css setting, avoid the title line-height changed */
+    line-height: 1.15;
+  }
+
+  .loading {
+    position: fixed;
+    top: 0;
+    left: 0;
+    z-index: 9999;
+    display: flex;
+    flex-direction: column;
+    align-items: center;
+    justify-content: center;
+    width: 100%;
+    height: 100%;
+    overflow: hidden;
+    background-color: #f4f7f9;
+
+    /* transition: all 0.8s ease-out; */
+  }
+
+  .loading.hidden {
+    pointer-events: none;
+    visibility: hidden;
+    opacity: 0;
+    transition: all 0.8s ease-out;
+  }
+
+  .dark .loading {
+    background: #0d0d10;
+  }
+
+  .title {
+    margin-top: 66px;
+    font-size: 28px;
+    font-weight: 600;
+    color: rgb(0 0 0 / 85%);
+  }
+
+  .dark .title {
+    color: #fff;
+  }
+
+  .loader {
+    position: relative;
+    width: 48px;
+    height: 48px;
+  }
+
+  .loader::before {
+    position: absolute;
+    top: 60px;
+    left: 0;
+    width: 48px;
+    height: 5px;
+    content: '';
+    background: hsl(var(--primary, 210 100% 50%) / 50%);
+    border-radius: 50%;
+    animation: shadow-ani 0.5s linear infinite;
+  }
+
+  .loader::after {
+    position: absolute;
+    top: 0;
+    left: 0;
+    width: 100%;
+    height: 100%;
+    content: '';
+    background: hsl(var(--primary, 210 100% 50%));
+    border-radius: 4px;
+    animation: jump-ani 0.5s linear infinite;
+  }
+
+  @keyframes jump-ani {
+    15% {
+      border-bottom-right-radius: 3px;
+    }
+
+    25% {
+      transform: translateY(9px) rotate(22.5deg);
+    }
+
+    50% {
+      border-bottom-right-radius: 40px;
+      transform: translateY(18px) scale(1, 0.9) rotate(45deg);
+    }
+
+    75% {
+      transform: translateY(9px) rotate(67.5deg);
+    }
+
+    100% {
+      transform: translateY(0) rotate(90deg);
+    }
+  }
+
+  @keyframes shadow-ani {
+    0%,
+    100% {
+      transform: scale(1, 1);
+    }
+
+    50% {
+      transform: scale(1.2, 1);
+    }
+  }
+</style>
+<!-- 中性 Loading 文案: 避免绑定 VITE_APP_TITLE / 站点名, 无需 i18n -->
+<div class="loading" id="__app-loading__">
+  <div class="loader"></div>
+  <div class="title">Loading...</div>
+</div>