- Session struct with UUID primary key, hashed refresh token, device
info, IP address, and last-active tracking
- Token generation via generateHashedToken (SHA-256, 128 random bytes)
- CreateSession, GetSessionByRefreshToken, GetSessionByID
- Atomic RotateRefreshToken with WHERE on old hash to prevent replays
- ReadAll scoped to authenticated user (link shares rejected)
- Delete scoped to owning user (link shares rejected)
- Hourly cleanup cron for expired sessions based on is_long_session
- ErrSessionNotFound error type with HTTP 404 mapping
