Task S2.1: the broker now checks consent (cmp.checkPurpose) after the OPA gate +
obligations and before the provider — a DENY blocks the send (BLOCKED/CONSENT_DENIED,
provider never called); ALLOW/NOT_REQUIRED proceed, ALLOW carrying the consent
receipt. Contracts gain CapabilityRequest.purpose + CapabilityResult.consentReceiptRef.
FakeCmp is now purpose-aware (denyPurpose/allowOnly). 5 new tests: allow+receipt,
deny→blocked, not-required, purpose-aware, OPA-before-CMP.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>