Client RealTimeNetworkAgent.SetNetworkInfo iterates the synchronize-data
dict in insertion order. The "uri" key, when recognized as Matched, calls
GameMgr.InitializeSelfInfo which sets _selfDeck = null. Any "selfDeck"
processed before "uri" gets wiped; Matching.StartBattleLoad then crashes
on null.Select(...). Pre-refactor ToJson built a Dictionary envelope-first
then appended body keys, so the bug never surfaced. The typed-body rewrite
inverted the order — restoring envelope-first matches the prod wire.
Regression test BuildMatched_KeyOrder_PutsUriBeforeSelfDeckAndSelfInfo
locks the contract.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
e4691d616b