refactor: improve handling of deployable fragments in ApplyRevision and buildPreviewFragments functions. Introduce isDeployableBirdFragment to filter out UI-only preview keys, and update related logic in the API to ensure proper job queuing and response handling for module refresh operations.

internal/birddeploy/apply.go

@@ -43,6 +43,9 @@ func ApplyRevision(ctx context.Context, ctl *birdfmt.BirdCtl, rev *store.Revisio
 	// Phase 1: write staging tree
 	for rel, content := range rev.PreviewFragments {
 		rel = strings.TrimPrefix(rel, "/")
+		if !isDeployableBirdFragment(rel) {
+			continue
+		}
 		dst := filepath.Join(staging, rel)
 		if err := os.MkdirAll(filepath.Dir(dst), 0o755); err != nil {
 			return err
@@ -70,6 +73,9 @@ func ApplyRevision(ctx context.Context, ctl *birdfmt.BirdCtl, rev *store.Revisio
 	// Phase 2: atomic swap into active
 	for rel, content := range rev.PreviewFragments {
 		rel = strings.TrimPrefix(rel, "/")
+		if !isDeployableBirdFragment(rel) {
+			continue
+		}
 		dst := filepath.Join(active, rel)
 		if err := os.MkdirAll(filepath.Dir(dst), 0o755); err != nil {
 			_ = restoreLKG(lkg, active)
@@ -93,6 +99,11 @@ func ApplyRevision(ctx context.Context, ctl *birdfmt.BirdCtl, rev *store.Revisio
 	return nil
 }
 
+// isDeployableBirdFragment skips UI-only preview keys (e.g. flattened full config) not referenced from bird.conf.
+func isDeployableBirdFragment(rel string) bool {
+	return rel != "" && !strings.HasPrefix(rel, "_")
+}
+
 func snapshotBirdTree(activeRoot, dstRoot string) error {
 	if err := os.MkdirAll(dstRoot, 0o755); err != nil {
 		return err