Function spawn_scanners 

pub fn spawn_scanners(
    pool: PgPool,
    cfg: PostgresScannerConfig,
) -> PostgresScannerHandle

Spawn all six Postgres reconcilers as long-lived tick loops.

Per-task shape:

1. Build a tokio::time::interval(cfg.<reconciler>_interval).
2. On each tick (or on shutdown signal), either run the reconciler tick body or exit.
3. Log per-tick failures at warn and continue — matches the Valkey scanner’s “don’t poison the scanner on one bad partition” semantic.