ToJson/FromJson round-trip the persistent global bank; play --save-state <file>
persists it, --state <file> restores it — so an expensive booted state (23646
globals) is captured once and reused without re-running *INIT, and it's the
foundation for real save-file work. Tests: unit round-trip + booted-state
survives snapshot (skill data intact). Engine 18/18.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>