fix(macos): gate drag region to macOS only

src/routes/+page.svelte

@@ -476,6 +476,7 @@
   // Title Bar State (from titleBarStore subscription)
   let showTitleBar = $state(shouldShowTitleBar());
   let showWindowControls = $state(getShowWindowControls());
+  const isMacOS = typeof document !== 'undefined' && document.documentElement.classList.contains('macos');
 
   // Search Bar Location State
   let searchBarLocationPref = $state(getSearchBarLocation());
@@ -4760,7 +4761,7 @@
 {:else}
   <div class="app" class:no-titlebar={!showTitleBar} class:floating={isWindowFloating}>
     <!-- macOS: drag region for window movement (overlay title bar has no native drag area) -->
-    {#if !showTitleBar}
+    {#if !showTitleBar && isMacOS}
       <div class="macos-drag-region" data-tauri-drag-region></div>
     {/if}
     <!-- Custom Title Bar (CSD) -->