* fix: create mayor/daemon.json during gt start and gt doctor --fix (#5)
- Add DaemonPatrolConfig type with heartbeat and patrol settings
- Add Load/Save/Ensure functions for daemon patrol config
- Create daemon.json in gt start (non-fatal if fails)
- Make PatrolHooksWiredCheck fixable with Fix() method
- Add comprehensive tests for both config and doctor checks
This fixes the issue where gt doctor expects mayor/daemon.json to exist
but it was never created by gt start or any other command.
* refactor: use constants.DirMayor instead of hardcoded string