Finish render rollout with markdown publish defaults, analyze guidance, and docs updates

internal/stage/analyze.go

@@ -670,6 +670,12 @@ func resolveScriptoriumInput(
 				return "", false, nil, fmt.Errorf("normalized transcript input is unavailable; run normalize stage first")
 			case artifacts.ArtifactTranscriptFinalTrimmed:
 				return "", false, nil, fmt.Errorf("trimmed transcript input is unavailable; run trim stage first")
+			case artifacts.ArtifactTranscriptFinalMarkdown, artifacts.ArtifactTranscriptFinalTrimmedMarkdown:
+				return "", false, nil, fmt.Errorf(
+					"rendered markdown transcript input is unavailable for source %q; run narratio run-stage --force render %s",
+					descriptor.Source.ID,
+					paths.SessionID,
+				)
 			default:
 				return "", false, nil, nil
 			}