Behavior-preserving; 271 BattleNode/Matching/Services tests green, full solution builds.
"BattleType" meant two things: the Sessions.BattleType enum (Pvp/Bot) and an int
"mode id" field. Renamed the int field on MatchContext AND the BattleStartBody wire
DTO to BattleModeId (wire key stays "battleType" via JsonPropertyName), so BattleType
now means only the enum project-wide.
New Bridge/BattleModes.cs (TakeTwo = 11) replaces every 11 literal — both prod
MatchContextBuilder sites and the test fixtures/assertions. The arbitrary-passthrough
42 and bot 0 stay literal.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Per-BattleId slot keyed dict. Pair returns the first arriver to the
second; ParkAsync awaits a TCS and returns the second arriver. Timeout
defaults to BattleNodeOptions.WaitingRoomTimeout (60s); evict on timeout
keeps the dict clean. Singleton in DI; consumed by the handler in the
next task.
