- Add PUT /users/me/password inline handler in routes_users.go
(the existing handler in internal/api/user/ was never registered)
- Create migration 975 adding two_factor_enabled, two_factor_secret,
and backup_codes columns to users table (fixes 500 on 2FA endpoints)
Fixes: Settings bugs #1 (password 404), #2/#4 (2FA 500)
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>