One-time, re-runnable, read-only importer that backfills NexaCloud
customers/plans/deployments into Odoo as a shadow copy for dual-run
reconciliation. Locks the brainstorming decisions: per-deployment
granularity, flat+overage billing, cpu_seconds metric, CPU-only v1,
Odoo-side psycopg2 reader, and shadow-safety by construction (draft
subs + no payment token + charges with NULL plan_id).