chore: Remove comment on secondary dedup key

Remove comment about secondary dedup key in content-hash.ts

Author: mikr13

src/lib/storage/content-hash.ts

@@ -6,7 +6,6 @@ const normalizePart = (value: string): string =>
     .trim()
     .replace(/\s+/g, " ");
 
-// Secondary dedup key: answer + category only (ignores question phrasing)
 export const buildAnswerKey = (answer: string, category: string): string =>
   `${normalizePart(answer)}||${normalizePart(category)}`;