DOCFIX-175/176: OpenTofu state file security + VR1 teardown/rollback runbook ...

Found while reviewing what's missing from the VR1 buildout ahead of
tomorrow's execution.

DOCFIX-175: terraform.tfstate stores sensitive=true variables (like
maas_api_key) in plaintext regardless of the flag, which only redacts
CLI/plan output (verified against HashiCorp's own docs). Added .gitignore
coverage, a "State file handling" section in opentofu/README.md, an inline
caveat on maas_api_key's description, and a "SECURE THE STATE FILE" callout
at Stage 1 Step 10 -- the actual first real tofu apply (an early draft
wrongly assumed Stage 3; corrected after reading the runbooks directly).

DOCFIX-176: new runbooks/dc-dc-teardown-rollback.md for the OpenTofu/
libvirt/MAAS-vm_host layer, which D-061's existing teardown scripts don't
cover (different layer, juju/MAAS-machine). Two paths (scoped -target
teardown or full VR1 destroy), a rollback decision tree favoring
fix-forward over destroy, and explicit mesh-link shared-infrastructure
handling.

Also folded in: a fix to docs/changelog-20260710-ledger-scan-self-inflicted-falsepositive-fix.md
after re-running ledger-scan.sh caught that its own narration (and the
session-ledger mirror) had reintroduced the exact false-positive class
DOCFIX-174 had just fixed.

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

DOCFIX-171: full-project sweep -- DC-DC runbook consistency fixes ...

Stage 1's calculator scripts (DOCFIX-162) were never wired into its own
Step 3 (still showed manual arithmetic) -- fixed to actually invoke them.
Stage 5's Sequence-list still tagged the IPv6 overlay [NOT YET WRITTEN]
after the Step 6 body was already updated -- fixed to match. Stage 6's
delivery checklist claimed its steps call the new Ceph replication
scripts when the step bodies still only showed raw commands -- added real
"PREFER scripts/dc-dc-..." pointers to each affected step. Also closed out
two DOCFIX numbers (164, 167) whose ledger entries never got their real
number written into the closing line during the earlier integration pass.

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

DOCFIX-153: Stage 1 runbook -- Phase 0 vcloud host preparation ...

Command-level runbook for turning the bare vcloud host into a VR1 substrate:
measure CPU/RAM/disk/nested-KVM/MTU, enable nested KVM, prepare storage pool
paths, install/confirm OpenTofu, write tfvars from measured values, init/
validate/plan/apply the DC1 planes + Office1 pool + mesh links, verify
against the Phase-0 gate. Flags a real open question (unconditional MAAS
provider block possibly demanding credentials before Stage 2 stands up
MAAS) rather than silently working around it. Not yet executed -- this is
the hand-off artifact for tomorrow morning's switch to the vcloud host.

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