DOCFIX-166: $DC parameterization for reenroll-hosts/carve-host-interfaces/phase-00-maas-standup (gap #15, CLI half) ...

Each script gained an opt-in $DC env var, calling lib_net_select_dc/
lib_hosts_select_dc immediately after sourcing (unset $DC is byte-for-byte
unchanged VR0/DC0 behavior -- verified directly, no fixtures needed since
the selector calls sit before any MAAS call). DC=dc1 bash
scripts/phase-00-maas-standup.sh is now a real, correct, gated call
(D-101 makes dc1's target identical to dc0's); DC=dc1/dc2 for the other
two scripts still fails loud at the host selector until real per-DC host
data exists. New/extended test cases across three harnesses. Six of gap
#15's seven sub-findings remain open -- said plainly, not overclaimed.

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

D-060: revert to Pattern A; supersede D-057/D-058 ...

Revert provider NIC to Pattern A (MAAS-built OVS br-ex) on the existing D-052/D-053 scheme. bundle.yaml clean bf7de5a checkout (provider-public x11, VIP triple .4/.8/.12, all 4 br-ex MACs); lib-net.sh + carve back to D-052/D-053; NEW provider-bundle-check.py gate; standup retargeted; teardown.sh + teardown runbook updated. Retire: phase-00-maas-recidr.sh, provider-vip-standup.sh, d057-bundle-check.py, and the 3 provider-vip/reconfigure runbooks.

MAAS script updates

Scripts update

Phase 0 updates