- DELETE /api/channels/{id}/messages/{msg_id} — soft delete, own only
- Broadcasts WsEvent::Delete to subscribers
- UI: "Del" button on hover for own messages (turns red)
- Fix layout: h-full + overflow-hidden on flex containers
- ScrollArea gets min-h-0 to properly constrain in flex
- Messages no longer push compose past viewport
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>