fix: skip Proxmox compute orchestration for unmanaged hosts (#455)

When a host is registered via Global Registration with a hostgroup that
has a Compute Resource (Proxmox), the compute orchestration methods
(setComputeUpdate, delComputeUpdate, setComputeDetails) are triggered
even though the host is unmanaged (managed: false). This causes errors
like "protected method setCompute called" because the orchestration
tries to interact with the Proxmox API for a host that was not
provisioned through Foreman.

This patch adds a managed? guard to skip Proxmox-specific compute
orchestration for unmanaged hosts. When the host is not managed, the
methods return true early, allowing the registration to proceed
without attempting to modify VM state on Proxmox.

Author: jakduch

app/models/concerns/orchestration/proxmox/compute.rb

@@ -26,6 +26,8 @@ def setComputeUpdate
         if compute_resource.class != ForemanFogProxmox::Proxmox
           super
         else
+          return true unless managed?
+
           logger.info "Update Proxmox Compute instance for #{name}"
           final_compute_attributes = compute_attributes.merge(compute_resource.host_compute_attrs(self))
           logger.debug("setComputeUpdate: final_compute_attributes=#{final_compute_attributes}")
@@ -40,6 +42,8 @@ def delComputeUpdate
         if compute_resource.class != ForemanFogProxmox::Proxmox
           super
         else
+          return true unless managed?
+
           logger.info "Undo Update Proxmox Compute instance for #{name}"
           final_compute_attributes = old.compute_attributes.merge(compute_resource.host_compute_attrs(old))
           compute_resource.save_vm uuid, final_compute_attributes
@@ -97,6 +101,8 @@ def setVmDetails
       def setComputeDetails
         if compute_resource.class != ForemanFogProxmox::Proxmox
           super
+        elsif !managed?
+          true
         elsif vm
           setVmDetails
         else