ops: appliance boot — wait for cameras/LiveKit, power button powers off

deploy/wait-for-cameras.sh

@@ -0,0 +1,17 @@
+#!/bin/bash
+# Wait for udev to pin C920 nodes after boot. Never fail the unit:
+# discovery can still run with whatever is present.
+set -u
+udevadm settle -t 20 || true
+udevadm trigger --subsystem-match=video4linux --action=add || true
+udevadm trigger --subsystem-match=sound --action=add || true
+for _ in $(seq 1 45); do
+  n=$(ls -1 /dev/cam[0-9][0-9] 2>/dev/null | wc -l)
+  if [ "$n" -ge 1 ]; then
+    echo "wait-for-cameras: $n pinned /dev/camNN nodes"
+    exit 0
+  fi
+  sleep 1
+done
+echo "wait-for-cameras: none yet; starting anyway" >&2
+exit 0