fix(sunshine): use Intel rendering and recover remote Niri sessions (#268)

- render Niri on the Intel iGPU while retaining NVIDIA-connected physical outputs
- encode Sunshine streams with Intel VAAPI and wait for a Niri output before startup
- load VKMS persistently for headless sessions and configure `Virtual-1` at 2560x1600@60
- let Moonlight request the stream bitrate instead of enforcing a 20 Mbps host cap
- remove unsupported Dynamic Boost and global NVIDIA session overrides
- grant Sunshine access to virtual input devices
- add a Nushell recovery helper that starts a temporary greetd/Niri session from SSH
- identify and safely replace normal, standalone, or previous transient Niri sessions
- launch the transient service in the background and verify greetd, Niri, and Sunshine before returning
- ignore local `.worktrees` directories and keep eval regression coverage focused on structural behavior

modules/nixos/desktop/networking/remote-desktop.nix

@@ -1,4 +1,10 @@
-{ lib, pkgs, ... }:
+{
+  config,
+  lib,
+  myvars,
+  pkgs,
+  ...
+}:
 {
   environment.systemPackages = with pkgs; [
     moonlight-qt # moonlight client, for streaming games/desktop from a PC
@@ -39,4 +45,6 @@
       wan_encryption_mode = 2;
     };
   };
+
+  users.users."${myvars.username}".extraGroups = lib.mkIf config.services.sunshine.enable [ "input" ];
 }