feat: add custom css for board and custom classes in advanced options for items (#512)

* feat: add custom css for board and custom classes in advanced options for items

* chore: add mysql migration

* fix: test not working

* fix: format issues

* fix: typecheck issue

* fix: build issue

* chore: add missing translations

* fix: merge issues related to migrations

* fix: format issues

* fix: merge issue with migration

* fix: format issue

apps/nextjs/src/app/[locale]/widgets/[kind]/_content.tsx

@@ -8,7 +8,7 @@ import type { IntegrationKind, WidgetKind } from "@homarr/definitions";
 import { useModalAction } from "@homarr/modals";
 import { showSuccessNotification } from "@homarr/notifications";
 import { useScopedI18n } from "@homarr/translation/client";
-import type { BoardItemIntegration } from "@homarr/validation";
+import type { BoardItemAdvancedOptions, BoardItemIntegration } from "@homarr/validation";
 import {
   loadWidgetDynamic,
   reduceWidgetOptionsWithDefaultValues,
@@ -42,9 +42,13 @@ export const WidgetPreviewPageContent = ({ kind, integrationData }: WidgetPrevie
   const [state, setState] = useState<{
     options: Record<string, unknown>;
     integrations: BoardItemIntegration[];
+    advancedOptions: BoardItemAdvancedOptions;
   }>({
     options: reduceWidgetOptionsWithDefaultValues(kind, {}),
     integrations: [],
+    advancedOptions: {
+      customCssClasses: [],
+    },
   });
 
   const handleOpenEditWidgetModal = useCallback(() => {