Add CanWritePlayer to IPlayerQuestStateStore and check before
prerequisite gate; map TryActivate/TryAdvanceStep store failures
from progress snapshots instead of always unknown_player.
Fix persistence test AAA layout, empty-id denial theory, frozen id constants,
Postgres rollback/JSONB read, XML doc cref, README Bruno link, and review doc.
Introduces IPlayerQuestStateStore (in-memory + V008 Postgres), QuestStepState
snapshots, DI wiring, AAA unit tests, and docs for E7M1-05 before NEO-117 ops.
VinPropane