fix(iac): drop vms/ — Orca does not provision VMs

Re-read the Orca spec: 'orca nodes' lists already-joined hosts and
'orca join' attaches an existing node to a cluster, but Orca does not
provision the VMs themselves. VM provisioning (SysEleven OpenStack
via Terraform) is a separate concern and will land in a dedicated repo
under the M1.2 milestone, not in orca-platform.

Removes vms/{vm-edge,vm-control,vm-data,stage}.toml + vms/README.md.
Updates README directory tree and milestone fill-in table to reflect
that M1.2's VM specs live elsewhere. validate.sh stops checking vms/.

Refs: M1.1

CHANGELOG.md

@@ -6,7 +6,7 @@ Generated section is appended on release tag via `git-cliff` (see `.gitea/workfl
 ## [Unreleased]
 
 ### Added
-- feat(iac): scaffold orca-platform — manifests/, overlays/, vms/, dns/, scripts/, Makefile (M1.1)
+- feat(iac): scaffold orca-platform — manifests/, overlays/, dns/, scripts/, Makefile (M1.1)
 -
 
 ### Changed