Add poweroff prompt to the end of the x86_64 installer.

x86_64/airootfs/usr/local/bin/install-stormux

@@ -2288,7 +2288,6 @@ else
     if [[ "$desktopEnvironment" == "i3" ]]; then
         log "  4. Your i3 desktop is configured with I38 for accessibility"
         log "     - I38 source is available in ~/git/I38 for customization"
-        log "     - Press Alt+Shift+F1 for I38 help after login"
     fi
 
     log ""
@@ -2298,7 +2297,21 @@ else
     # Play success sound
     play_success_sound
     finalExitCode=0
+    promptPoweroff=true
+fi
+
+if [[ "${promptPoweroff:-false}" == true ]]; then
+    echo ""
+    read -rp "Power off this installation media now? [y/N]: " poweroffChoice
+    if [[ "$poweroffChoice" =~ ^[Yy]$ ]]; then
+        log_info "Powering off the installation media"
+        poweroff
+        log_warning "Poweroff command failed. To power off later, type: poweroff"
+    else
+        log "Leaving the installer. To power off later, type: poweroff"
+    fi
+else
+    read -rp "Press Enter to exit..."
 fi
 
-read -rp "Press Enter to exit..."
 exit "$finalExitCode"