chore(opentofu): drop the spent removed block for module.k8s_3

The removal has been applied:

  Apply complete! Resources: 0 added, 0 changed, 0 destroyed, 1 forgotten.

`tofu state list` now returns no Proxmox resources at all, and a full plan with
refresh enabled produces no Proxmox errors — the "no route to host" against
10.2.40.201:8006 that failed every infrastructure plan since the conversion is
gone.

The block was always one-shot. Left in place it refers to a state entry that no
longer exists, which is harmless but misleading: it reads as pending work.

Worth recording for the next time this shape comes up, because it cost a failed
merge to learn. A `removed` block alone does not fix an unreachable provider:
OpenTofu still refreshes the resource before it can forget it, and that refresh
is exactly what cannot succeed. It takes one run with `-refresh=false` to
process. `-target` does not help — targeting does not reach `removed` blocks, so
a targeted plan reports "No changes" while the state entry sits there untouched.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

opentofu/removed_k8s_3.tf

@@ -1,27 +0,0 @@
-# k8s-3 was the last Proxmox VM. neptune now runs Talos on bare metal, and its
-# disks were wiped during the conversion, so the VM this module described does
-# not exist in any form.
-#
-# `removed` rather than simply deleting vm_152_k8s_3.tf: dropping the resource
-# from configuration alone makes OpenTofu plan a DESTROY, and planning a destroy
-# refreshes the resource through the bpg/proxmox provider — which now has no
-# endpoint to reach. That is exactly what has been failing every infrastructure
-# plan since the conversion:
-#
-#   Error: failed to get resources list of type ("vm") for cluster:
-#   dial tcp 10.2.40.201:8006: connect: no route to host
-#     with module.k8s_3.proxmox_virtual_environment_vm.this
-#
-# `lifecycle { destroy = false }` forgets the state entry without attempting to
-# contact Proxmox. Nothing is orphaned by doing so: the guest, its disks and the
-# hypervisor underneath it are all already gone.
-#
-# This block can be deleted once one plan has run cleanly with it — it is a
-# one-shot instruction, not standing configuration.
-removed {
-  from = module.k8s_3
-
-  lifecycle {
-    destroy = false
-  }
-}