DC-DC Stage 1 (dc-dc-phase0): first real execution + scaffold/tooling fixes ...

First end-to-end run of a DC-DC runbook against real infrastructure (vcloud host,
OpenTofu v1.12.3). Applied 13 libvirt objects (6 DC1 planes, dc1/office1/dc2
pools, office1-local, 3 mesh legs, all MTU 9000); prior VR0 nets torn down (wan
kept as a gap-#17 model); DC2 planes deferred (NetBox supernet), DC2 storage wired.

DOCFIX-178: scripts/prereqs/ idempotent workstation prereq installers + a
  Prerequisites section in the runbook + tests/prereqs/ (25/25). Runbooks must
  not assume prereq runtimes.
DOCFIX-179: OpenTofu scaffold first validation + apply. Per-module
  required_providers (child modules do NOT inherit provider SOURCE -> OpenTofu
  inferred nonexistent hashicorp/libvirt); tofu fmt -recursive; provider "maas"
  deferred to Stage 3 (kept a sensitive key out of Stage-1 plan/state);
  repo-lint now skips the .terraform/ provider cache; .terraform.lock.hcl added.
DOCFIX-180: dc-dc-phase0 runbook as-executed corrections folded in at phase
  close (two MTU domains, non-pristine-host handling, Step-9 13-resource plan,
  -input=false, Known-Gap resolved).

repo-lint 0 fail; prereqs harness 25/25; repo-lint harness 34/34.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

DOCFIX-142: opentofu/ network + storage-pool scaffold (VR1 IaC, gap #2) ...

First OpenTofu content in the repo. Network/pool layer only: modules/dc-planes
(the six per-DC planes, D-052/D-100), modules/mesh-link (the D-100 dark-fiber
triangle), modules/dc-storage-pool, wired for DC1 (inherits DC0's CIDRs per
D-101) and Office1. DC2 deliberately not wired -- its CIDRs aren't assigned
yet (D-101 open sub-item).

Provider schema (dmacvicar/libvirt v0.9.8) verified against its actual current
docs this session, not memory -- it has diverged materially from older common
examples (network isolation is a nested forward.mode, not top-level mode;
libvirt_domain restructured to ~40 args mirroring raw libvirt XML). Node-VM/
volume resources, OPNsense config, and tc netem application are deliberately
deferred: that schema is too large/unfamiliar to author safely without a real
`tofu providers schema` pass on a connected machine -- see opentofu/README.md
for the full account and the concrete next step.

Added scripts/opentofu-validate.sh (fmt/init/validate wrapper) + a harness
testing what's actually exercisable without a tofu binary (none is available
anywhere this repo has been worked in this session -- logged, not hidden).
Extended repo_lint.py's L1 check to cover .tf files (uncovered before since
none existed). repo-lint 0 fail / 1 documented warn; both harnesses green.
Workflow doc + its companion visual tracker updated to match.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QrcJx8TUar7pYAvpGJw57A