Behavior-preserving; 231 BattleNode tests green.
FrameDispatchContext.BothAfterReady() -> BothSidesAfterReady() (7 call sites). The
4 inline `SenderPhase == AfterReady` checks in TurnEndHandler/TurnEndFinalHandler now
read a new SenderIsAfterReady property. Both carry cross-referencing docs so the
Bot-arm (sender-only) vs PvP-arm (both-sides) distinction is explicit at the type.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>