feat: Add scripts and systemd services for SteamOS session management and game launching

ansible/files/game_station/bin/system/steamos-session-select

@@ -0,0 +1,40 @@
+#!/bin/bash
+set -euo pipefail
+LOGFILE="$HOME/.local/logs/session.log"
+
+log() { echo "[$(date --iso-8601=seconds)] $*" | tee -a "$LOGFILE"; }
+
+session="${1:-gamescope}"
+
+case "$session" in
+  plasma*)
+    log "Plasma session selected."
+    touch "$HOME/.desktop-session-plasma"
+  ;;
+  gamescope)
+    log "Gamescope session selected."
+    if [[ -f "$HOME/.desktop-session-plasma" ]]; then
+      rm "$HOME/.desktop-session-plasma"
+    fi
+  ;;
+  *)
+    log "!! Unrecognized session '$session'"
+    exit 1
+  ;;
+esac
+
+if systemctl --user is-active --quiet steam.scope; then
+  log "Stopping steam.scope"
+  systemctl --user stop steam.scope
+fi
+if systemctl --user is-active --quiet plasma.scope; then
+  log "Stopping plasma.scope"
+  systemctl --user stop plasma.scope
+fi
+if systemctl --user is-active --quiet sunshine.scope; then
+  log "Stopping sunshine.scope"
+  systemctl --user stop sunshine.scope
+fi
+
+log "Restarting graphical session service..."
+systemctl --user restart session.service