fix: use buildCtx for image wait and recalculate duration

Addresses PR review feedback:
1. Use buildCtx instead of ctx for waitForImageReady to respect
   build timeout during image conversion wait
2. Recalculate duration after waitForImageReady completes to
   accurately report total build time including image conversion

Author: hiroTamada

lib/builds/manager.go

@@ -301,16 +301,24 @@ func (m *manager) runBuild(ctx context.Context, id string, req CreateBuildReques
 	// Wait for image to be ready before reporting build as complete.
 	// This fixes the race condition (KERNEL-863) where build reports "ready"
 	// but image conversion hasn't finished yet.
-	if err := m.waitForImageReady(ctx, id); err != nil {
+	// Use buildCtx to respect the build timeout during image wait.
+	if err := m.waitForImageReady(buildCtx, id); err != nil {
+		// Recalculate duration to include image wait time
+		duration = time.Since(start)
+		durationMS = duration.Milliseconds()
 		m.logger.Error("image conversion failed after build", "id", id, "error", err, "duration", duration)
 		errMsg := fmt.Sprintf("image conversion failed: %v", err)
 		m.updateBuildComplete(id, StatusFailed, nil, &errMsg, &result.Provenance, &durationMS)
 		if m.metrics != nil {
-			m.metrics.RecordBuild(ctx, "failed", duration)
+			m.metrics.RecordBuild(buildCtx, "failed", duration)
 		}
 		return
 	}
 
+	// Recalculate duration to include image wait time for accurate reporting
+	duration = time.Since(start)
+	durationMS = duration.Milliseconds()
+
 	m.updateBuildComplete(id, StatusReady, &result.ImageDigest, nil, &result.Provenance, &durationMS)
 
 	// Update with image ref
@@ -320,7 +328,7 @@ func (m *manager) runBuild(ctx context.Context, id string, req CreateBuildReques
 	}
 
 	if m.metrics != nil {
-		m.metrics.RecordBuild(ctx, "success", duration)
+		m.metrics.RecordBuild(buildCtx, "success", duration)
 	}
 }