Starts Postgres as an OS-level child of the BEAM via Port.open/2.

When BEAM exits (including SIGKILL), a shell watchdog kills Postgres too. No PID files, no stale processes.

If Postgres is already running on the configured port, joins as a guest and does not own the lifecycle. See README for details.

Usage

children = [
  {PgSpawner, port: 15432, pgdata: "priv/db/data"}
]