feat(ui): ✨ enable text selection in markdown preview and overlay (#221)

Co-authored-by: Jorben <jorbenzhu@gmail.com>

Author: HayWolf

src/modules/workbench-shell/ui/file-editor-view.tsx

@@ -317,7 +317,7 @@ const MarkdownPreview: FC<MarkdownPreviewProps> = ({ content, workspaceId, fileP
   );
 
   return (
-    <div className="h-full overflow-auto bg-app-canvas/70 px-4 py-3 text-app-foreground">
+    <div className="h-full overflow-auto bg-app-canvas/70 px-4 py-3 text-app-foreground select-text">
       <div className="mx-auto max-w-4xl text-sm leading-6">
         <MessageResponse components={components}>{content}</MessageResponse>
       </div>

src/modules/workbench-shell/ui/workbench-preview-overlay.tsx

@@ -58,7 +58,7 @@ export function WorkbenchPreviewOverlay({
         </div>
 
         {/* Content */}
-        <div className="min-h-0 flex-1 overflow-auto bg-app-canvas/70">
+        <div className="min-h-0 flex-1 overflow-auto bg-app-canvas/70 select-text">
           {children}
         </div>
       </div>