Add the gfcloud full-cloud controller daemon

gfcloud runs the machine under the Glowforge web service (the factory
cloud experience: the app drives homing, framing, printing). Its init
service starts it only when controller_mode = cloud - mutually exclusive
with grblHAL, which already stands down for that mode - so it owns
/dev/glowforge exclusively. Persistent GFUIService loop with a clean
SIGTERM shutdown that safes the hardware; the init script mirrors
grblhal.init. The image installs gfcloud and python3-ffmachine.

meta-forgefirm/recipes-forgefirm/gfcloud/files/gfcloud.init

@@ -0,0 +1,49 @@
+#!/bin/sh
+### BEGIN INIT INFO
+# Provides:          gfcloud
+# Required-Start:    $local_fs $network
+# Required-Stop:
+# Default-Start:     2 3 4 5
+# Default-Stop:      0 1 6
+# Short-Description: Glowforge web-service controller (full cloud mode)
+### END INIT INFO
+
+DAEMON=/usr/sbin/gfcloud.py
+PIDFILE=/var/run/gfcloud.pid
+CONF=/data/forgefirm.conf
+
+# Boot-time controller-mode dispatch, mirror of grblhal.init: this daemon
+# runs the machine under the Glowforge web service. It starts only when
+# controller_mode = cloud (which keeps grblHAL down); anything else - grbl,
+# unset, or no config file - leaves it stopped.
+controller_mode() {
+    [ -r $CONF ] || { echo grbl; return; }
+    m=$(sed -n 's/^[ \t]*controller_mode[ \t]*=[ \t]*\([a-z]*\).*/\1/p' $CONF | tail -n 1)
+    echo "${m:-grbl}"
+}
+
+case "$1" in
+  start)
+    if [ "$(controller_mode)" != "cloud" ]; then
+      echo "gfcloud not started (controller_mode != cloud)"
+      exit 0
+    fi
+    echo "Starting gfcloud"
+    start-stop-daemon -S -q -p $PIDFILE -m -b -x $DAEMON
+    ;;
+  stop)
+    echo "Stopping gfcloud"
+    start-stop-daemon -K -q -p $PIDFILE
+    rm -f $PIDFILE
+    ;;
+  restart)
+    $0 stop
+    sleep 2
+    $0 start
+    ;;
+  *)
+    echo "Usage: $0 {start|stop|restart}"
+    exit 1
+    ;;
+esac
+exit 0