Turn the displays off while the headset isn't used, and keep it awake on a charger

A display mount that covers the proximity sensor makes the headset seem
worn, so SteamVR never turned its displays off and they stayed on all
night. The new power service, ft-powerd (frametop-power.service), goes by
use instead: after DISPLAY_OFF_MIN minutes in which the headset and
controllers didn't move and no input device was used, it turns the
backlight off, and the next movement or input turns it back on.

The new Power tab in Frametop Display Settings sets that time and has a
Stay awake while plugged in switch. The switch sets Steam's own "When
Plugged In and Idle -> Sleep after" to Never through Steam's UI, so the
Frame stays reachable remotely while the power button still works.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

power/build.sh

@@ -0,0 +1,9 @@
+#!/usr/bin/env bash
+# Build ft-powerd on the Frame, in the dev container (it also runs there).
+set -euo pipefail
+root=$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)
+"$root/scripts/sync.sh" >/dev/null
+exec "$root/scripts/frame.sh" -C power 'set -e; mkdir -p build
+g++ -std=c++17 -O2 -Wall -Wno-unused-parameter -I/opt/steamvr/tools/hellovr_vulkan_linux/src/openvr/headers \
+  -o build/ft-powerd ft-powerd.cpp -L/opt/steamvr/bin/linuxarm64 -lopenvr_api -Wl,-rpath,/opt/steamvr/bin/linuxarm64
+echo "built build/ft-powerd"'