fix: 停用登录设备绑定(注释 machine 写入/重绑与 check_login 不一致拒绝)便于多设备/联调；Vue 首页背景图改 /bg.jpg 并补 public 资源、首页/登录布局居中修复

frontend-vue/src/pages/home/DesktopHomePage.vue

@@ -271,13 +271,18 @@ onMounted(() => {
 body {
   font-family: "Microsoft YaHei", "PingFang SC", "Hiragino Sans GB", sans-serif;
   background: linear-gradient(rgba(255, 255, 255, 0.5), rgba(255, 255, 255, 0.5)),
-    url("/static/bg.jpg") center/cover no-repeat;
+    url("/bg.jpg") center/cover no-repeat;
+  min-height: 100vh;
+}
+
+.home-root {
   min-height: 100vh;
   display: flex;
   flex-direction: column;
   align-items: center;
   justify-content: center;
   padding: 40px;
+  box-sizing: border-box;
 }
 
 .header {

frontend-vue/src/pages/login/DesktopLoginPage.vue

@@ -216,11 +216,16 @@ body {
   font-family: "Microsoft YaHei", "PingFang SC", "Hiragino Sans GB", sans-serif;
   background: #d8e4ec;
   min-height: 100vh;
+}
+
+.legacy-login-root {
+  min-height: 100vh;
   display: flex;
   flex-direction: column;
   align-items: center;
   justify-content: center;
   padding: 40px;
+  box-sizing: border-box;
 }
 
 .header {