fix build preview path

Author: techniq

.github/workflows/build-preview.yml

@@ -30,5 +30,5 @@ jobs:
         uses: actions/upload-artifact@v4
         with:
           name: preview-build
-          path: packages/svelte-ux/.svelte-kit
+          path: sites/docs/.svelte-kit
           include-hidden-files: true