docs: update Phase 11 commit hash in REFACTOR.md

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Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: bordeux

REFACTOR.md

@@ -666,7 +666,7 @@ These should NOT become filters (they require context, have side effects, or are
 - [x] Run `cargo make qa`
 - [x] Update REFACTOR.md with current state
 
-**Commit:** (pending)
+**Commit:** 4399e70
 
 ### Phase 12: Kubernetes Functions