the 15s no-message watchdog and the 30s stall watchdog treat a quiet local PDS as a dead relay, so the dev firehose drained itself between deploys and missed events. in dev-pds mode (development or test only, a local PDS only, no secondary relay, Bun runtime) the subscription passes maxSilenceMs null and checks liveness with websocket ping/pong instead, and the stall watchdog stands down. a peer that stops answering pings is still dropped and reconnected; pongs never count as messages. relay mode is unchanged. ported from the effect-migration branch's approach without the rest of that rewrite.