- add user twofa fields and migration
- add 2FA setup/enable/disable endpoints
- enforce OTP on login when 2FA enabled
- add web login OTP field and settings UI
- add user last_seen_at with alembic migration and persist on realtime disconnect
- extend chat serialization with private online/last_seen, group members/online, channel subscribers
- add Redis batch presence lookup helper
- update web chat list/header to display status counters and last-seen labels
- improve delivery receipt handling using last_delivered/last_read boundaries
- include chat info panel and related API/type updates
backend:
- add required user name and optional bio fields
- extend auth/register and user schemas/services with name/bio
- add alembic migration 0006 with safe backfill name=username
- compute per-user chat display_title for private chats
- keep Saved Messages delete-for-all protections
web:
- registration now includes name
- add profile edit modal (name/username/bio/avatar url)
- show private chat names via display_title
- fix context menus to open near cursor with viewport clamping
- stabilize +/close floating button to remove visual jump
