- MessageBubble: role hidden by default, appears on hover of sender name (group/name CSS)
- Direct chat header: shows other user's role (from otherUserRole field added to backend)
- @mention: typing @ triggers filtered user dropdown, click inserts @Name into message
- Hint text updated: '@ — упомянуть'
- Backend: other_user_role added to rooms query
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>