## Summary Feature flag rollout issue for `short_ttl_approval_cache`. This feature flag gates a short-TTL (30-second) Redis cache for MR approval state in the mergeability check framework. When enabled, `CheckApprovedService` caches its result using a fingerprint-based cache key that automatically invalidates when approval rules or approvals change. ### What does the feature flag do? When enabled, the `CheckApprovedService` mergeability check becomes cacheable with a 30-second TTL. This avoids repeated expensive approval computations during UI/API polling. - Cache key includes a fingerprint of both MR-level and project-level approval rules plus current approvals - Cache is automatically bypassed during actual merge operations (`use_cache: false`) - 30-second TTL provides a safety net for any edge cases the fingerprint doesn't capture ### MR !227379