fix: relay shutdown, claim lease, dead-letter undecodable, dedup window

crates/adapters/nats/src/consumer.rs

@@ -106,6 +106,12 @@ fn consume_from_rx(rx: EnvelopeRx) -> BoxStream<'static, Result<EventEnvelope, D
     }))
 }
 
+/// How long JetStream remembers `Nats-Msg-Id`s. A row re-relayed within this
+/// window (crash between publish and mark-done, or a lease reclaim) is dropped
+/// by the broker; beyond it the consumer ledger is the backstop. Set
+/// explicitly so it does not silently follow the server default.
+const DEDUP_WINDOW: std::time::Duration = std::time::Duration::from_secs(60 * 60);
+
 // ── JetStream consumer ────────────────────────────────────────────────────────
 
 pub struct NatsJetStreamConsumer {
@@ -121,6 +127,7 @@ impl NatsJetStreamConsumer {
                 name: cfg.stream_name.clone(),
                 subjects: vec![consumer_subject_filter(&cfg.subject_prefix)],
                 max_messages: 100_000,
+                duplicate_window: DEDUP_WINDOW,
                 ..Default::default()
             })
             .await?;