Add environment.d config for gamescope HDR

environment.d/gamescope-session.conf

@@ -0,0 +1,10 @@
+if [ "$XDG_SESSION_DESKTOP" = "gamescope" ] ; then
+    SCREEN_WIDTH=2560
+    SCREEN_HEIGHT=1440
+    SCREEN_HZ=360
+    CONNECTOR=*,DP-1
+    CLIENTCMD="steam -gamepadui -pipewire-dmabuf"
+    GAMESCOPECMD="/usr/bin/gamescope --hdr-enabled --hdr-itm-enable \
+    --hide-cursor-delay 3000 --fade-out-duration 200 --xwayland-count 2 \
+    -W $SCREEN_WIDTH -H $SCREEN_HEIGHT -r SCREEN_HZ -O $CONNECTOR"
+fi