修复首屏：增加预加载占位并提前恢复主题

app/spa-loading-template.html

@@ -0,0 +1,62 @@
+<!-- 业务脚本未就绪时使用独立样式；Nuxt 在首个页面解析完成后自动移除此模板。 -->
+<div
+  id="console-startup"
+  role="status"
+  aria-label="页面加载中"
+  aria-live="polite"
+>
+  <img src="/images/brand/logo.png" alt="破碎工坊云" width="168" height="36" />
+  <span class="startup-spinner" aria-hidden="true"></span>
+  <p>正在加载控制台</p>
+  <noscript>请启用 JavaScript 后刷新页面。</noscript>
+</div>
+<style>
+  #console-startup {
+    position: fixed;
+    inset: 0;
+    z-index: 9999;
+    display: flex;
+    flex-direction: column;
+    align-items: center;
+    justify-content: center;
+    gap: 24px;
+    box-sizing: border-box;
+    padding: 24px;
+    background: #f8fafc;
+    color: #334155;
+    font:
+      14px/1.5 system-ui,
+      sans-serif;
+  }
+  .app-dark #console-startup {
+    background: #18181b;
+    color: #e4e4e7;
+  }
+  #console-startup img {
+    width: 168px;
+    height: 36px;
+    object-fit: contain;
+  }
+  #console-startup p {
+    margin: 0;
+  }
+  #console-startup .startup-spinner {
+    width: 28px;
+    height: 28px;
+    box-sizing: border-box;
+    border: 3px solid #94a3b833;
+    border-top-color: #2563eb;
+    border-radius: 50%;
+    animation: startup-spin 0.8s linear infinite;
+  }
+  @keyframes startup-spin {
+    to {
+      transform: rotate(360deg);
+    }
+  }
+  @media (prefers-reduced-motion: reduce) {
+    #console-startup .startup-spinner {
+      animation: none;
+    }
+  }
+</style>