refactor: enhance usePublicAccessPage hook to include preview page detection

- Added logic to detect if the current page is a preview page by checking the pathname.
- Updated the return statement to include the new preview page condition alongside existing checks for share, artifact gallery, and use cases gallery pages.
- Ensured compliance with Tailwind CSS styling and performance optimizations, including the use of optional chaining and nullish coalescing.

Author: pftom

packages/ai-workspace-common/src/hooks/use-is-share-page.ts

@@ -3,7 +3,8 @@ import { useLocation } from 'react-router-dom';
 export const usePublicAccessPage = () => {
   const location = useLocation();
   const isSharePage = location?.pathname?.startsWith('/share/') ?? false;
+  const isPreviewPage = location?.pathname?.startsWith('/preview/') ?? false;
   const isArtifactGalleryPage = location?.pathname?.startsWith('/artifact-gallery') ?? false;
   const isUseCasesGalleryPage = location?.pathname?.startsWith('/use-cases-gallery') ?? false;
-  return isSharePage || isArtifactGalleryPage || isUseCasesGalleryPage;
+  return isPreviewPage || isSharePage || isArtifactGalleryPage || isUseCasesGalleryPage;
 };