Add reconciliation state foundation

internal/config/defaults.go

@@ -42,6 +42,11 @@ const (
 	LinkPrimarySource = "source"
 )
 
+const (
+	ReconciliationModeReplace = "replace"
+	ReconciliationModeMerge   = "merge"
+)
+
 const DefaultS3Region = "us-east-1"
 
 const (
@@ -79,6 +84,9 @@ func ApplyDefaults(cfg *Config) {
 			if destination.Links != nil && destination.Links.Primary == "" {
 				destination.Links.Primary = LinkPrimaryAuto
 			}
+			if destination.Reconciliation.Mode == "" {
+				destination.Reconciliation.Mode = ReconciliationModeReplace
+			}
 			if destination.Transfer.OnDestinationSame == "" {
 				destination.Transfer.OnDestinationSame = TransferActionSkip
 			}