Attach custom-instance datatables in the DuckDB executor through a DuckDB
secret instead of an inline connection string, and route postgres triggers on
custom-instance datatables through a dedicated custom_instance_replication_user
role (with its own auto-generated password in global_settings). Normalize
custom_instance_user attributes on server boot.
Claude-Session: https://claude.ai/code/session_01Tp6NNNinCB8dwWqGaFXDRF
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
