Spawns attic/elphel-agent-tools/bin/cpu_profile_hold.py on startup,
which calls power-profiles-daemon HoldProfile('balanced') via DBus.
Released automatically via SIGTERM on JVM shutdown.

Design: KDE AC default is power-saver; this hold raises the profile to
balanced (hardware-driven boost under load) while ImageJ is running,
then releases it so the machine drops back to power-saver on exit.
Co-authored-by: Claude <claude@elphel.com>