Serve never converts databases: with no paskia.kantadb it points at
'paskia init', or at 'paskia migrate' when legacy *.paskiadb candidates
exist. migrate converts a lone candidate, or the one named by --rp-id
when several exist; the rest stay in place. devserver fails fast with
the same hint. gitignore covers paskia.kantadb and *.converted-bak.
Add comprehensive remote authentication system allowing users to log in from one device by authenticating from another trusted device. Features include:
- Proof of Work (PoW) protection using PBKDF2-SHA512 to prevent abuse
- Simple pairing codes (3 words) protected by dynamic PoW difficulty
- Autocomplete pairing code input with error checking
- Real-time WebSocket communication between devices
Unlike device addition links and reset links with QR codes that only allow adding an authentication method, and that work offline over the duration of several days, this mechanism is strictly online, with 5 minute time limit.