PPPOE-HA: deployed to production

Mechanism installed on both routers (--check clean against git on both),
`interfaces pppoe pppoe0 disable` removed from vyos002, and vyos002 is out of
FAULT and holding BACKUP on all six groups for the first time in 3d10h -- the
lab has a real standby again.

Verified on the wire rather than from state: with a tcpdump running on
vyos002's bond0.51 across the commit, ZERO PADI/PADR. The peers file rendered
(so it can dial the instant it is promoted) while ConditionResult stayed `no`
and NRestarts 0. vyos001's live session was untouched throughout -- same
MainPID 2931, same 83.106.5.72, internet 7.6-8.4ms at 0% loss.

Not done, deliberately: the controlled failover drill, which interrupts the
household's internet, and merging the staged Pulumi override, which lands via
another agent's `pulumi up` on a branch they have checked out.

migration/PPPOE-HA.md

@@ -1,6 +1,8 @@
 # PPPoE high availability
 
-Proven in labsim. **Not applied to production.**
+Proven in labsim. **Deployed to production 2026-09-06** — mechanism on both
+routers, `pppoe0 disable` removed from vyos002, vyos002 out of FAULT and in
+BACKUP. The Pulumi override (step 8) is still staged, not merged.
 
 ## What it does