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.