feat: the power button does nothing, and one chord opens a terminal

Two layers for the button, because one is not enough: while a session is
running PowerDevil holds logind's handle-power-key inhibitor and acts on
the button itself, so a logind drop-in alone would be overruled. logind
covers the machine before the session starts, after it ends, and if
PowerDevil is not running. Verified: after the drop-in is installed and
logind reloaded, it reports ignore for the power, suspend, hibernate and
lid keys, and the running session was not disturbed by the reload.

Holding the button still cuts the power. That is firmware, below any
operating system, and it is deliberately left alone as the only recovery
a person standing at a wedged machine has.

The maintenance terminal is Meta+Ctrl+Alt+Shift+K, declared in the
package rather than seeded into a teacher's configuration, where an
update could not reach it. KGlobalAccel read it and registered the
component; invoking it opened a working shell.

It needed a wrapper. The classroom's Kiosk policy sets shell_access=false
and Konsole honours it — measured: with the classroom configuration in
its cascade Konsole starts and says "Program to run not set." The
restriction is worth keeping everywhere else, so it is lifted for this
one process by leaving the classroom's configuration directory out of
its cascade. It grants no privilege: the classroom user has no sudo
rule, and that restriction was always a barrier in the interface rather
than a privilege boundary.

Konsole's own entry is shadowed and hidden from /usr/local/share, so
nothing is patched and Konsole's package stays maintainable. Nothing is
pinned to the panel; a task button appears only while a terminal is
open, and closing it returns the bar to three launchers.

Co-Authored-By: Claude Opus 5 <[email protected]>

packaging/debian/control.template

@@ -4,7 +4,7 @@ Section: misc
 Priority: optional
 Architecture: amd64
 Maintainer: Ekklesia
-Depends: plasma-desktop, plasma-workspace, kwin-wayland, plasma-nm, plasma-pa, plasma-widgets-addons, sddm, dbus-user-session, xwayland, fonts-dejavu, fonts-noto, network-manager, pipewire, pipewire-audio, wireplumber, pulseaudio-utils, cups, cups-client, cups-filters, foomatic-db-compressed-ppds, python3-gi, python3-gi-cairo, gir1.2-gtk-3.0, gir1.2-gtklayershell-0.1, libnotify-bin, curl, gnupg, ca-certificates, python3-paho-mqtt
+Depends: plasma-desktop, plasma-workspace, kwin-wayland, plasma-nm, plasma-pa, plasma-widgets-addons, konsole, sddm, dbus-user-session, xwayland, fonts-dejavu, fonts-noto, network-manager, pipewire, pipewire-audio, wireplumber, pulseaudio-utils, cups, cups-client, cups-filters, foomatic-db-compressed-ppds, python3-gi, python3-gi-cairo, gir1.2-gtk-3.0, gir1.2-gtklayershell-0.1, libnotify-bin, curl, gnupg, ca-certificates, python3-paho-mqtt
 Recommends: vlc
 Conflicts: plasma-welcome, plasma-discover, kdeconnect, kup-backup
 Description: Ekklesia managed classroom environment
@@ -14,6 +14,11 @@ Description: Ekklesia managed classroom environment
  left here is the church's own subject matter — Wonder Ink, the browser,
  the DVD player, the printer, the audio policy and the updater.
  .
+ konsole is here for one chord. It is the local recovery route for a
+ technical administrator standing at a machine when SSH is not
+ available; it is hidden from every application list and reachable only
+ by Meta+Ctrl+Alt+Shift+K.
+ .
  plasma-widgets-addons is here for one widget: Quick Launch, which is
  the only stock way to put a single launcher on the panel that reads
  /usr/share/applications live. The Icon widget copies the entry into the

packaging/debian/postinst

@@ -46,6 +46,12 @@ chmod 0640 /etc/ekklesia-classroom/device.conf
 
 systemctl daemon-reload || true
 
+# The power button stops working immediately rather than at the next
+# boot. Verified in the lab: logind re-reads its drop-ins on reload and
+# reports ignore afterwards, and the running graphical session is not
+# disturbed by it.
+systemctl reload systemd-logind >/dev/null 2>&1 || true
+
 # Autologin into the classroom, and back into it if the session ever ends.
 systemctl enable sddm.service >/dev/null 2>&1 || true