docs: update opentofu migration plan with current state

- ns2 migrated to OpenTofu
- testvm02, testvm03 added to managed hosts
- Remove vaulttest01 (no longer exists)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

docs/plans/host-migration-to-opentofu.md

@@ -9,14 +9,13 @@ hosts are decommissioned or deferred.
 
 ## Current State
 
-Hosts already managed by OpenTofu: `vault01`, `testvm01`, `vaulttest01`
+Hosts already managed by OpenTofu: `vault01`, `testvm01`, `testvm02`, `testvm03`, `ns2`
 
 Hosts to migrate:
 
 | Host | Category | Notes |
 |------|----------|-------|
 | ns1 | Stateless | Primary DNS, recreate |
-| ns2 | Stateless | Secondary DNS, recreate |
 | nix-cache01 | Stateless | Binary cache, recreate |
 | http-proxy | Stateless | Reverse proxy, recreate |
 | nats1 | Stateless | Messaging, recreate |
@@ -95,11 +94,12 @@ Migrate stateless hosts in an order that minimizes disruption:
 
 1. **nix-cache01** — low risk, no downstream dependencies during migration
 2. **nats1** — low risk, verify no persistent JetStream streams first
-4. **http-proxy** — brief disruption to proxied services, migrate during low-traffic window
+3. **http-proxy** — brief disruption to proxied services, migrate during low-traffic window
-5. **ns1, ns2** — migrate one at a time, verify DNS resolution between each
+4. **ns1** — ns2 already migrated, verify AXFR works after ns1 migration
 
-For ns1/ns2: migrate ns2 first (secondary), verify AXFR works, then migrate ns1. All hosts
+~~For ns1/ns2: migrate ns2 first (secondary), verify AXFR works, then migrate ns1.~~ ns2
-use both ns1 and ns2 as resolvers, so one being down briefly is tolerable.
+migration complete. All hosts use both ns1 and ns2 as resolvers, so ns1 being down briefly
+during migration is tolerable.
 
 ## Phase 4: Stateful Host Migration