- 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 chats.public_id random identifier with migration 0011
- expose public_id in chat API payloads
- use chat public_id in message search UI label
- fix users router order so /users/blocked no longer conflicts with /users/{user_id}