pi_standard_setup, pi_hifiberry_amp and pi_disable_onboard_bluetooth each defined a
handler called "Reboot". Handler names are play-global, so a notify ran only the last
one defined - pi_disable_onboard_bluetooth's - and with that role's `when:`. On every
host where onboard Bluetooth stays on, the handler was skipped and nothing that asked
for a reboot ever got one: not a changed dtoverlay, not a hostname change, not the Pi 5
kernel. Seen on musicdolphin, where a new HiFiBerry overlay sat unapplied in
config.txt after a clean run.
Each role now notifies a handler only it defines.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>