IMatchingBridge.RegisterPendingBattle now takes a MatchContext; PendingBattle
carries it; BattleSession stores it. ArenaTwoPickBattleController builds ctx
from IMatchContextBuilder. ScriptedLifecycle still uses ScriptedProfiles for
the player half — Tasks 5/6 migrate the lifecycle.
Existing tests updated: MatchingBridgeTests, BattleNodeFlowTests,
InMemoryBattleSessionStoreTests, BattleSessionDispatchTests, BattleSession
PumpTests, ArenaTwoPickBattleControllerTests (which now seeds a TK2 run +
adds a no-active-run 400 case).
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
