Fix real-deployment blockers and scope down to router-only VMs

Confirmed working against a real VK Cloud PROD deployment (3 routers,
19 resources, apply succeeded end to end). Fixes found along the way:

- provider "vkcs" was never configured (versions.tf) - username/password/
  project_id/region were declared but wired to nothing; added auth_url and
  user_domain_name to complete it.
- Nova keypairs are per-user, not per-project - added an optional
  vkcs_compute_keypair resource (var.ssh_public_key) so Terraform can
  register a keypair under the deploying service account itself.
- router_priv_port used a hand-computed fixed_ip offset that collided with
  VKCS's own auto-created service ports on each network (observed: a
  "network:dns" port) - now left unset so Neutron's IPAM auto-assigns,
  which is collision-free by construction.
- vkcs_compute_instance set image_id at the top level while also booting
  from a volume via block_device - the provider docs say not to do this;
  Nova echoes back a sentinel string for image_id on a volume-booted
  server, which Terraform read as drift on a ForceNew attribute and
  wanted to destroy+recreate every already-created instance on every
  subsequent plan.
- private_network_cidrs bumped from /29 to /28 - too tight once the
  platform's own reserved ports are accounted for.

Also removed the priv_srv_01/02/03 demo instances and the LAN network/
security group only they used - this deployment provisions router VMs
only, confirmed with the user.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011hXR2ftXZZhJ4Y3XuSoR8r

.gitignore

@@ -11,9 +11,17 @@ __pycache__/
 .terraform.lock.hcl
 *.tfstate
 *.tfstate.*
+*.tfplan
 crash.log
 crash.*.log
 
+# Real credentials layered on top of terraform.tfvars (see terraform/prod.auto.tfvars.example) -
+# terraform.tfvars itself stays a committed, anonymized template; auto-loaded
+# overrides with real secrets must never be committed.
+*.auto.tfvars
+*.auto.tfvars.json
+terraform.tfvars.local
+
 # Claude Code session-local runtime state (not project content)
 .claude/scheduled_tasks.lock
 .claude/*.lock