fix: restore desktop mixin lost during upstream sync

UsagePage.module.scss uses @include desktop which was removed from
mixins.scss when syncing upstream. Add it back with min-width: 1025px
breakpoint (tablet + 1).

Author: NGLSL

src/styles/mixins.scss

@@ -17,6 +17,12 @@
   }
 }
 
+@mixin desktop {
+  @media (min-width: #{$breakpoint-tablet + 1}) {
+    @content;
+  }
+}
+
 // 文本截断
 @mixin text-ellipsis {
   overflow: hidden;