feat(core-consent): add PayloadConsent, RecordingConsent and DI binders

Implements the Payload-backed IConsent that reads/writes users.consentState
and emits CONSENT_GRANT/CONSENT_WITHDRAW audit entries via injected auditLog.
Adds RecordingConsent test double in core-testing for unit-test injection.
Adds bindProductionConsent/bindDevSeedConsent DI binders and InMemoryConsent
for dev/seed contexts. Contract tests cover grant/withdraw/isGranted round-trip,
audit entry shape, metadata persistence (bannerVersion/policyVersion/method),
and getCategories reflection of state.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

packages/core-testing/src/instrumentation/index.ts

@@ -11,3 +11,7 @@ export {
   type RecordedIdentify,
   type RecordedPageView,
 } from "./recording-analytics";
+export {
+  RecordingConsent,
+  type RecordedConsentGrant,
+} from "./recording-consent";