With a fixed --unit name, the rule fails to start when a unit from a
previous power event still exists, leaving the power profile stale.
Letting systemd-run generate unique unit names keeps every trigger
working; --collect still garbage-collects each unit on exit.
Ports 749a8c04 from master.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
