- Chat input @ autocomplete: typing @ shows online users (room users +
online friends + room aliases) with avatars; arrows/Tab/Enter to pick.
- Any valid @nick token is highlighted blue in chat bubbles (like @all),
giving visual feedback that it is a recognised mention.
- Side notification toast on a received mention: sender avatar (from the
new senderFigure wire field) + message + dismiss; dismiss marks it read
so the toolbar unread badge updates. Auto-hides after 8s.
- IMentionEntry/parsers carry senderFigure end to end.
duckietm