Fix virt-manager Flatpak command for Bazzite

- Update virt-manager Flatpak command from org.virt-manager.virt-manager to org.virt_manager.virt-manager
- This matches the actual Flatpak installation on Bazzite
- Update both noble and trixie wrapper scripts
- Update usage guide with correct command
- Maintain all Bazzite-specific VM creation instructions

usage-guide.sh

@@ -45,6 +45,12 @@ echo "   • --vm: Run in isolated VM with virsh (full isolation)"
 echo "   • --help: Show usage information and safety warnings"
 echo "   • Interactive prompts for direct host execution"
 echo ""
+echo "📋 Bazzite/Immutable Distro Notes:"
+echo "   • virt-manager is installed as Flatpak"
+echo "   • virt-install may not be available by default"
+echo "   • Podman containers are recommended for testing"
+echo "   • Use 'ujust install libvirt-clients' if needed"
+echo ""
 
 echo "⚠️  Safety Notes:"
 echo "   • Test in a VM first"
@@ -80,4 +86,17 @@ echo ""
 
 echo "🔄 Rollback:"
 echo "   sudo apt install --reinstall libostree-dev libostree-1-1 ostree"
-echo "   # Reinstall original packages from distribution repositories" 
+echo "   # Reinstall original packages from distribution repositories"
+echo ""
+echo "🔧 Bazzite VM Creation:"
+echo "   # Option 1: Use virt-manager (Flatpak)"
+echo "   flatpak run org.virt_manager.virt-manager"
+echo ""
+echo "   # Option 2: Use toolbox for virt-install"
+echo "   toolbox create --distro fedora"
+echo "   toolbox enter"
+echo "   sudo dnf install virt-install"
+echo ""
+echo "   # Option 3: Use Podman containers (recommended)"
+echo "   ./backport-noble.sh --podman"
+echo "   ./backport-trixie.sh --podman"