Enforce requested adapter output paths

internal/stage/polish.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
-	"os"
 	"path/filepath"
 	"strings"
 
@@ -131,17 +130,17 @@ func (polishStage) Run(ctx context.Context, env *Env, m *manifest.Manifest) (*St
 		return nil, fmt.Errorf("polish: audita polish failed: %w", err)
 	}
 
-	finalProcessedPath := processedPath
-	if strings.TrimSpace(res.ProcessedTranscriptPath) != "" {
-		finalProcessedPath = res.ProcessedTranscriptPath
+	finalProcessedPath, err := authoritativeOutputPath(processedPath, res.ProcessedTranscriptPath)
+	if err != nil {
+		return nil, fmt.Errorf("polish: %w", err)
 	}
 	if err := validateProcessedTranscriptOutput(finalProcessedPath); err != nil {
 		return nil, fmt.Errorf("polish: processed transcript %q invalid: %w", finalProcessedPath, err)
 	}
 
-	finalReportPath := req.ReportPath
-	if strings.TrimSpace(res.ReportPath) != "" {
-		finalReportPath = res.ReportPath
+	finalReportPath, err := authoritativeOutputPath(req.ReportPath, res.ReportPath)
+	if err != nil {
+		return nil, fmt.Errorf("polish: %w", err)
 	}
 	if reportEnabled {
 		if err := validateTranscriptJSONFile(finalReportPath); err != nil {
@@ -246,38 +245,7 @@ func (polishStage) Run(ctx context.Context, env *Env, m *manifest.Manifest) (*St
 }
 
 func discoverMergedTranscript(m *manifest.Manifest, paths artifacts.SessionPaths) (string, string, error) {
-	candidates := make([]string, 0)
-	if m != nil && m.Stages != nil {
-		if sr := m.Stages["merge"]; sr != nil {
-			for _, out := range sr.Outputs {
-				if out.Kind != "transcript_base" {
-					continue
-				}
-				p := strings.TrimSpace(out.LocalPath)
-				if p == "" {
-					continue
-				}
-				resolved := artifacts.ResolveSessionLocalPathForRead(paths, p)
-				candidates = append(candidates, filepath.Clean(resolved))
-			}
-		}
-	}
-
-	deduped := dedupeAndSortPaths(candidates)
-	for _, p := range deduped {
-		if info, err := os.Stat(p); err == nil && !info.IsDir() {
-			return p, "manifest.merge.outputs", nil
-		}
-	}
-
-	fallback := filepath.Join(paths.TranscriptsDir, "base.json")
-	if info, err := os.Stat(fallback); err == nil && !info.IsDir() {
-		return filepath.Clean(fallback), "fallback.transcripts_dir", nil
-	}
-	if len(deduped) > 0 {
-		return deduped[0], "manifest.merge.outputs", nil
-	}
-	return "", "", nil
+	return resolveSingletonTranscript(m, paths, artifacts.ArtifactTranscriptBase)
 }
 
 func validateProcessedTranscriptOutput(path string) error {