2b0cd516f0
Swaps 6 JstPeriod.* callsites in mission code to IGameCalendarService. Also drops the manual `jstNow = now.ToOffset(+9).AddHours(-2)` shift in MissionAssembler — BP monthly missions now key off UTC calendar month, and the start/end wire timestamps become UTC-midnight month boundaries. This matches the plan's all-UTC discipline; wire fidelity for BP monthlies is not shipped yet. Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>