Add feature gate changes to changelog JSON output

The changelog JSON output (`oc adm release info --changelog --output=json`)
was missing feature gate change data that was only available in the
markdown output. This adds a `featureGates` field to the ChangeLog JSON
struct, populated using the existing `calculateFeatureSetDiff()` logic.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: stbenjam

pkg/cli/admin/release/info.go

@@ -1777,6 +1777,32 @@ func describeChangelog(out, errOut io.Writer, releaseInfo *ReleaseInfo, diff *Re
 				})
 			}
 		}
+		if featureSetDiff, err := calculateFeatureSetDiff(diff); err != nil {
+			fmt.Fprintf(errOut, "error: unable to calculate feature gate diff: %v\n", err)
+			hasError = true
+		} else {
+			orderedFeatureGates := featureSetDiff.GetOrderedFeatureGates()
+			allFeatureSets := featureSetDiff.AllFeatureSets()
+			allFeatureSets.Delete("LatencySensitive") // this was a dead-end featureset we removed.
+			allClusterProfiles := featureSetDiff.AllClusterProfiles()
+			for _, fg := range orderedFeatureGates {
+				fgInfo := ChangeLogFeatureGateInfo{
+					Name:   fg,
+					Status: map[string]map[string]string{},
+				}
+				for _, cp := range sets.List(allClusterProfiles) {
+					fgInfo.Status[cp] = map[string]string{}
+					for _, fs := range sets.List(allFeatureSets) {
+						if diffInfo := featureSetDiff.FeatureInfoFor(cp, fs); diffInfo != nil {
+							if change, ok := diffInfo.ChangedFeatureGates[fg]; ok {
+								fgInfo.Status[cp][fs] = change
+							}
+						}
+					}
+				}
+				changeLog.FeatureGates = append(changeLog.FeatureGates, fgInfo)
+			}
+		}
 		if len(added) > 0 {
 			for _, k := range added {
 				changeLog.NewImages = append(changeLog.NewImages, refToChangeInfo(diff.ChangedImages[k].To))
@@ -2712,11 +2738,19 @@ type ChangeLog struct {
 	From ChangeLogReleaseInfo `json:"from"`
 	To   ChangeLogReleaseInfo `json:"to"`
 
-	Components    []ChangeLogComponentInfo `json:"components,omitempty"`
-	NewImages     []ChangeLogImageInfo     `json:"newImages,omitempty"`
-	RemovedImages []ChangeLogImageInfo     `json:"removedImages,omitempty"`
-	RebuiltImages []ChangeLogImageInfo     `json:"rebuiltImages,omitempty"`
-	UpdatedImages []ChangeLogImageInfo     `json:"updatedImages,omitempty"`
+	Components    []ChangeLogComponentInfo    `json:"components,omitempty"`
+	FeatureGates  []ChangeLogFeatureGateInfo  `json:"featureGates,omitempty"`
+	NewImages     []ChangeLogImageInfo        `json:"newImages,omitempty"`
+	RemovedImages []ChangeLogImageInfo        `json:"removedImages,omitempty"`
+	RebuiltImages []ChangeLogImageInfo        `json:"rebuiltImages,omitempty"`
+	UpdatedImages []ChangeLogImageInfo        `json:"updatedImages,omitempty"`
+}
+
+// ChangeLogFeatureGateInfo describes the state of a feature gate across cluster profiles and feature sets.
+type ChangeLogFeatureGateInfo struct {
+	Name string `json:"name"`
+	// Status maps clusterProfile -> featureSet -> status string (e.g. "Enabled (Changed)", "Disabled (New)")
+	Status map[string]map[string]string `json:"status"`
 }
 
 type ChangeLogReleaseInfo struct {