The plan feature (the executing-plans skill, the plan/checks/constraints/testing
commands, the PlanReminder/ConstraintReminder/TestingReminder/WorkingState hooks and
the planExecution() config profile) has moved to its own package; code-commandments
is about code, not about grinding a plan.

A consumer's config still carries the planExecution() block an earlier sync injected,
and Config no longer has the method, so sync now strips that statement through the AST
before anything loads the config. Migration format 5 deletes the .plan-* session files
rather than converting them.

Journal: todos done remove-plan-execution/1
Journal: todos done remove-plan-execution/2
Journal: todos done remove-plan-execution/3
Journal: todos done remove-plan-execution/4
Journal: todos done remove-plan-execution/5