acpi.ec_no_wakeup=1 stops EC interrupts from thrashing s2idle, and a
dconf system-db override disables gsd-power's sleep handlers so logind
owns all sleep/idle policy (gsd was re-waking before HibernateDelaySec).
Split lid/suspend policy by power source (s-t-h on battery, plain suspend
on AC), map power key to hibernate, drop HibernateDelaySec to 15min while
re-validating thermals, and disable USB-device wakeup via udev.
