Ephemeral over the chat WebSocket (no DB). Composer emits chat-typing on/off
(throttled 2.5s, auto-stop after 4s idle / on send / on leaving the chat).
Server relays to the DM peer or fans out to group members (membership-checked).
Receiver shows 'typing…' in the conversation header subtitle and the sidebar
row preview (brand-blue italic), with per-sender auto-expiry so a dropped 'off'
can't stick. Group shows names ('Alice is typing…', 'N people are typing…').
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Sravan
3f791cb120