Merge PR: code review improvements and fix TypeScript errors

- Merge origin/claude/multi-agent-code-review-97LHj
- Fix DOMPURIFY_CONFIG TypeScript error (remove 'as const')
- Clean up local branches (e2e-problems-batch-*)
- Install missing dependencies

Author: davidagustin

lib/constants.ts

@@ -103,4 +103,4 @@ export const DOMPURIFY_CONFIG = {
   ],
   ALLOWED_ATTR: ['class', 'href', 'target', 'rel'],
   ALLOW_DATA_ATTR: false,
-} as const;
+};