Swift BLKillSwitchClient.check() sets isDisabled/maintenanceMessage as
properties on the client, not a returned result. Expose isDisabled and
maintenanceMessage as computed properties on the wrapper.
- Create Shared/Cloud/Config.swift with shared BLPlatformConfig for ChronoMind
- Create Shared/Cloud/KillSwitchService.swift thin wrapper over BLKillSwitchClient
Part of Mobile DRY Refactoring Roadmap Phase 9A.