PanelBoss

Keeps a Windows desk running itself when nobody is at it, and gets out of the way when somebody is.

Download PanelBoss 0.3.6 (MSI) Source & issues Companion extension

Presence from a local camera. Frames never leave the machine. No account, no cloud, works fully offline; detection stays off until you switch it on.
Per-monitor away modes. Dim, blackout, signal disconnect, or the panel's own DDC/CI power code, with a 10-second preview and honest words when a write is refused.
OLED care. The taskbar and background darken with the rest of the desk, a periodic pixel wash spreads static wear, and macro-pad and KVM fake input can't keep the desk bright.
Movie theater. The optional Companion extension makes the darkness hug the playing video — it sends window geometry only, never page content. The browser chrome and the rest of the desk go dark; the film keeps its light.
Game rates. A fullscreen game gets the refresh rate you set for that panel, VRR pin-max included.
Desk memory. Window positions come back after any wake, and whole monitor setups save as profiles keyed to the hardware.

Movie theater mode: darkness hugs a playing video, the rest of the desk dims — Movie theater mode. The extension sends geometry only; everything else is the app's own business.

MIT licensed. Per-user MSI: no admin, no UAC. Unsigned by choice until users justify the bill - the sha256 of every build is on the release page, and the built-in updater checks the download against it before installing. Nothing phones home; the only network request the app can ever make is the one behind the Check for updates button.
NVIDIA note: the DDC/CI power-off mode starts grayed because resumes from it have frozen some NVIDIA-driver machines (0x133) - seen without PanelBoss running too. AMD and Intel get it on day one.