Add Dynu Terraform brownfield DNS documentation layer

docs/terraform-workflows.md

@@ -43,6 +43,21 @@ Use for existing Proxmox VMs and metadata reconciliation.
 5. Keep lifecycle ignore rules narrow and explicit.
 6. Iterate per VM until plan stabilizes.
 
+
+## Dynu DNS workflow
+
+Directory: `infrastructure/terraform/dynu/`
+
+Use for existing Dynu domains and DNS records.
+
+1. Add or confirm the documentation catalog entry for one hostname.
+2. Confirm the provider resource type and import ID format.
+3. Import one existing domain or DNS record at a time.
+4. Inspect state with `terraform state show`.
+5. Reconcile only stable, meaningful attributes into hand-maintained `.tf`.
+6. Keep record IDs, dynamic DNS targets, and provider-computed values out unless intentionally required.
+7. Re-run plan until intended scope is clean.
+
 ## Physical host metadata workflow
 
 Physical host metadata currently lives in Proxmox Terraform locals/outputs and is used as documentation inventory context.