What's Changed
- fix(a2a-server): clear stale cancellation error on new message turns by @amelidev in #28940
- fix(core): declare top-level safety checkers in write policy configuration by @luisfelipe-alt in #28961
- (FIX) history rollback and retry nudge optimizations by @DavidAPierce in #28934
Full Changelog: v0.56.0-nightly.20260824.g5411f113c...v0.56.0-nightly.20260825.g812f7a2bc