docs: note to establish hostname naming conventions before migration

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

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

@@ -158,6 +158,12 @@ For each stateful host, the procedure is:
 coordinator state in `/var/lib/zigbee2mqtt` should preserve pairings, but verify on a
 non-critical time window.
 
+**USB Passthrough:** The ha1 VM has a USB device passed through from the Proxmox hypervisor
+(the Zigbee coordinator). The new VM must be configured with the same USB passthrough in
+OpenTofu/Proxmox. Verify the USB device ID on the hypervisor and add the appropriate
+`usb` block to the VM definition in `terraform/vms.tf`. The USB device must be passed
+through before starting Zigbee2MQTT on the new host.
+
 ## Phase 5: Decommission jump Host
 
 1. Verify nothing depends on the jump host (no SSH proxy configs pointing to it, etc.)
@@ -182,3 +188,8 @@ the same cleanup steps as the jump host.
   the new one is provisioned (or use a temporary IP and swap after verification)
 - Stateful migrations should be done during low-usage windows
 - After all migrations are complete, the only hosts not in OpenTofu will be ca (deferred)
+- Since many hosts are being recreated, this is a good opportunity to establish consistent
+  hostname naming conventions before provisioning the new VMs. Current naming is inconsistent
+  (e.g. `ns1` vs `nix-cache01`, `ha1` vs `auth01`, `pgdb1` vs `http-proxy`). Decide on a
+  convention before starting migrations — e.g. whether to always use numeric suffixes, a
+  consistent format like `service-NN`, role-based vs function-based names, etc.