- Change _fail2ban_connection_handler() to return generic message instead of
leaking socket path in HTTP 502 response body
- Change _fail2ban_protocol_handler() to return generic message instead of
leaking raw exception details in HTTP 502 response body
- Full error details are still logged server-side (error=str(exc)) for debugging
- Update Backend-Development.md with error message hygiene section explaining
the pattern: generic user-friendly messages in HTTP responses, full details
in server logs only
Fixes TASK-029: Fail2BanConnectionError leaks socket path in HTTP error responses
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>