fix(markdown): handle unavailable reply quote links

src/lib/utils/quote-link-utils.ts

@@ -0,0 +1,17 @@
+import type { Comment } from '@bitsocialhq/bitsocial-react-hooks';
+
+export const formatQuoteNumber = (number?: number) => `>>${number ?? '?'}`;
+
+export const isUnavailableQuoteTarget = (comment?: Partial<Pick<Comment, 'deleted' | 'removed'>> | null) => Boolean(comment?.deleted || comment?.removed);
+
+export const shouldShowFloatingQuotePreview = ({
+  hoveredCid,
+  outOfViewCid,
+  quoteCid,
+  isUnavailable,
+}: {
+  hoveredCid: string | null;
+  outOfViewCid: string | null;
+  quoteCid?: string;
+  isUnavailable?: boolean;
+}) => Boolean(quoteCid && !isUnavailable && hoveredCid === quoteCid && outOfViewCid === quoteCid);