ConfigRevision responses omit scheduledPublishAt/lock fields that are persisted (spec/back-end)

[Kevin-Chant]

Behavior: config-revisions schedule-publish returns 200 and the schedule persists (mongo-verified scheduledPublishAt, scheduledPublishLockEdits, scheduledPublishLockOthers on the revision doc), but the ConfigRevision API response omits all three fields — before and after scheduling. FeatureRevision responses include them. CLI behavior is correct; users just can't see or verify a schedule via the API/CLI.

Fix location: back-end ConfigRevision response serializer/spec (growthbook repo). No CLI patch/overlay carried.