Adds README sections covering the three-phase domain rule evaluation order, the
available match fields and operators, the keep-a-copy forwarding behaviour, the
webhook retry/backoff model, the signing headers, and the new API surface, plus
screenshots of both pages.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PGeWDVSkXtVEmDAN2AtB9h
