Step 2: dc-plane-ipam.sh carve-v6 --commit, applied=5, each GUA /64 on the same vlan as
its v4 twin and read back. 2 errors are correct refusals (lbaas-mgmt and oob have no v4
plane to pair with). Independent read: 11 v6 subnets, 6 GUA + 5 ULA, every GUA paired.

Step 3: dc-node-v6-carve.py replace --v6-family gua --commit, applied=45 skipped=9
errors=0, READ-BACK 45/45. Independent query: PRE 54 v6 links (GUA 9 / ULA 45) -> POST 54
(GUA 54 / ULA 0), and ZERO NICs carry more than one global v6, so G19's sole-global
predicate holds. v4 was not touched -- the ordering step 3 exists to enforce.

Gates after: dc-node-v6-carve check --v6-family gua PASS (54 correct, 0 missing, 0
errors); dc-plane-ipam check 29 pass / 2 fail, both expected absences and neither new
(lbaas-mgmt is step 5, oob has no MAAS plane). Was 7 fail before step 2.

Reversible: replace --v6-family ula --commit. Nothing was deleted; both families remain
in MAAS until step 6 retires the ULA rows. vr1-dc1 untouched.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HvCyrwvYTTcDYnRErfMsNf