Cleaned up and removed legacy configuration surfaces

internal/stage/analyze.go

@@ -649,15 +649,6 @@ func resolveScriptoriumInput(
 		return "", false, nil, err
 	}
 	switch source {
-	case "previous_session_artifact":
-		if strings.TrimSpace(inputCfg.Path) == "" {
-			return "", false, nil, nil
-		}
-		resolved := resolveInputPathForRead(paths, sessionDir, inputCfg.Path)
-		if err := requireFile(resolved, "scriptorium input "+inputName); err != nil {
-			return "", false, nil, nil
-		}
-		return resolved, true, nil, nil
 	default:
 		resolved, err := artifacts.ResolveSessionArtifactWithCatalog(paths, m, source, runtimeCatalog)
 		if err == nil {