# OCI Referrer Publishing

## Module
ExportCenter

## Status
IMPLEMENTED

## Description
OCI referrer push client and discovery service for publishing attestations as OCI-attached artifacts.

## Implementation Details
- **Referrer push client**: `src/ExportCenter/StellaOps.ExportCenter/StellaOps.ExportCenter.WebService/Distribution/Oci/OciReferrerPushClient.cs` -- pushes attestations as OCI referrer artifacts
- **Referrer discovery**: `src/ExportCenter/StellaOps.ExportCenter/StellaOps.ExportCenter.WebService/Distribution/Oci/OciReferrerDiscovery.cs` -- discovers attached referrer artifacts
- **Referrer discovery service**: `src/ExportCenter/StellaOps.ExportCenter/StellaOps.ExportCenter.WebService/Distribution/Oci/OciReferrerDiscoveryService.cs` -- service wrapper for referrer discovery
- **Referrer fallback**: `src/ExportCenter/StellaOps.ExportCenter/StellaOps.ExportCenter.WebService/Distribution/Oci/OciReferrerFallback.cs` -- fallback for tag-based referrer linking
- **RVA publisher**: `src/ExportCenter/StellaOps.ExportCenter/StellaOps.ExportCenter.WebService/Distribution/Oci/RvaOciPublisher.cs` -- publishes RVA attestations as OCI referrers
- **AI attestation publisher**: `src/ExportCenter/StellaOps.ExportCenter/StellaOps.ExportCenter.WebService/Distribution/Oci/AIAttestationOciPublisher.cs` -- AI attestation referrer publishing
- **AI attestation discovery**: `src/ExportCenter/StellaOps.ExportCenter/StellaOps.ExportCenter.WebService/Distribution/Oci/AIAttestationOciDiscovery.cs` -- discovers AI attestation referrers
- **Mirror referrer discovery**: `src/ExportCenter/StellaOps.ExportCenter/StellaOps.ExportCenter.Core/MirrorBundle/IReferrerDiscoveryService.cs`
- **Tests**: `src/ExportCenter/StellaOps.ExportCenter/StellaOps.ExportCenter.Tests/Distribution/Oci/OciReferrerPushClientTests.cs`, `OciReferrerDiscoveryTests.cs`, `OciReferrerDiscoveryServiceTests.cs`, `RvaOciPublisherTests.cs`, `Adapters/MirrorAdapterReferrerDiscoveryTests.cs`
- **Source**: Feature matrix scan

## E2E Test Plan
- [ ] Verify attestations are published as OCI referrer artifacts
- [ ] Test referrer discovery finds attached artifacts for a digest
- [ ] Verify fallback works for registries without referrer API
- [ ] Test RVA and AI attestation referrer publishing
- [ ] Verify mirror adapter discovers referrers across mirrors