Add persistent state storage for Witness across wisp burns: - Add WorkerState and WitnessHandoffState types - Implement loadHandoffState/saveHandoffState for bead persistence - Update getNudgeCount/recordNudge to use persistent state - Add activity tracking integration into healthCheck 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>