Serialize typed artifacts at durable boundaries

internal/framework/pipeline/checkpoint.go

@@ -75,6 +75,46 @@ type NormalizeCheckpoint struct {
 	Warnings []contracts.Warning
 }
 
+// ArtifactCheckpointOutput is the durable, domain-neutral value stored at a
+// typed lane checkpoint boundary.
+type ArtifactCheckpointOutput struct {
+	LaneID       string
+	ModuleKey    string
+	SourceID     string
+	ChunkID      string
+	ChunkIndex   int
+	ChunkRef     source.SourceRef
+	Artifact     contracts.SerializedArtifact
+	SchemaDigest string
+}
+
+type ArtifactExtractCheckpoint struct {
+	Outputs  []ArtifactCheckpointOutput
+	Rejected []contracts.RejectedOutput
+	Warnings []contracts.Warning
+}
+
+type ArtifactMergeCheckpoint struct {
+	Output   ArtifactCheckpointOutput
+	Warnings []contracts.Warning
+}
+type ArtifactNormalizeCheckpoint struct {
+	Output   ArtifactCheckpointOutput
+	Warnings []contracts.Warning
+}
+
+type ArtifactCheckpointRecorder interface {
+	ArtifactExtractSucceeded(string, string, []CheckpointFingerprint, []ArtifactCheckpointOutput, []contracts.RejectedOutput, []contracts.Warning) error
+	ArtifactMergeSucceeded(string, string, []CheckpointFingerprint, ArtifactCheckpointOutput, []contracts.Warning) error
+	ArtifactNormalizeSucceeded(string, string, []CheckpointFingerprint, ArtifactCheckpointOutput, []contracts.Warning) error
+}
+
+type ArtifactCheckpointLoader interface {
+	ArtifactExtract(string, string, []CheckpointFingerprint) (ArtifactExtractCheckpoint, CheckpointDecision)
+	ArtifactMerge(string, string, []CheckpointFingerprint) (ArtifactMergeCheckpoint, CheckpointDecision)
+	ArtifactNormalize(string, string, []CheckpointFingerprint) (ArtifactNormalizeCheckpoint, CheckpointDecision)
+}
+
 type CheckpointLoader interface {
 	Enabled() bool
 	Source(moduleKey string) (SourceCheckpoint, CheckpointDecision)