Wire QuestStateOperations.TryAccept at POST /game/players/{id}/quests/{questId}/accept
with shared quest row projection, integration tests, and Bruno accept flows.
Introduces IPlayerQuestStateStore (in-memory + V008 Postgres), QuestStepState
snapshots, DI wiring, AAA unit tests, and docs for E7M1-05 before NEO-117 ops.