System Base contract

System Base is global and uses an allowlisted table set. Resolve table, record and field IDs from the server.
Read the schema and current record/cell before an update. Preserve the current expected value and record_version.
Update only the explicitly requested cell and use a fresh idempotency key.
Deletion requires an explicit request, confirm=true, the current expected version and persisted readback.
Keep System Base separate from project AirBase data; do not invent table names or broaden filters.