refactor: Move recipe generator to cook/ directory and fix flattening bugs

- Move recipe-generator/ to cook/ for cleaner structure

- Fix ksflatten-relative path conversion to handle all %include paths

- Fix validation exit code to only fail on actual errors

- All recipes now generate and flatten successfully via make all

cook/ingredients/live/hypervisor.ks

@@ -0,0 +1,14 @@
+# Live desktop hypervisor configuration
+
+# Enable virtualization support in live environment
+%packages
+qemu-kvm
+libvirt-client
+virt-install
+%end
+
+%post --erroronfail
+# Setup libvirt for live environment
+mkdir -p /var/lib/libvirt
+systemctl enable libvirtd
+%end