Bound external reference reads and fingerprints

internal/framework/pipeline/handoff.go

@@ -243,6 +243,7 @@ type generatedReferenceFingerprintIdentity struct {
 	SchemaDigest     string `json:"schema_digest"`
 	MediaType        string `json:"media_type"`
 	ContentDigest    string `json:"content_digest"`
+	SizeBytes        int64  `json:"size_bytes"`
 }
 
 // generatedReferenceDependencies returns the canonical semantic dependency
@@ -271,6 +272,7 @@ func generatedReferenceDependencies(set contracts.ReferenceSet) []CheckpointFing
 				SchemaDigest:     contracts.DigestArtifactSchema(item.ArtifactSchema),
 				MediaType:        item.MediaType,
 				ContentDigest:    item.Digest,
+				SizeBytes:        item.SizeBytes,
 			}
 			encoded, err := json.Marshal(identity)
 			if err != nil {