feat: event ids, outbox identity migration

crates/bootstrap/src/event_bus.rs

@@ -26,23 +26,14 @@ impl EventBusBackend {
     }
 }
 
+/// The server's publisher is always the outbox writer: it never talks to the
+/// bus, whatever `EVENT_BUS_BACKEND` says. The worker owns delivery.
 pub async fn create_publisher(
     db_pool: &sqlx::SqlitePool,
     config: &config::AppConfig,
 ) -> anyhow::Result<Arc<dyn EventPublisher>> {
-    match EventBusBackend::from_config(&config.events)? {
-        EventBusBackend::Db => {
-            tracing::info!("event bus: DB queue");
-            Ok(sqlite::SqliteEventQueue::create_publisher(db_pool.clone(), &config.events).await?)
-        }
-        #[cfg(feature = "nats")]
-        EventBusBackend::Nats => {
-            let cfg = nats::NatsConfig::from_config(&config.nats)
-                .context("EVENT_BUS_BACKEND=nats requires NATS_URL to be set")?;
-            tracing::info!("event bus: NATS ({})", cfg.url);
-            Ok(nats::create_publisher(cfg).await?)
-        }
-    }
+    tracing::info!("event publisher: outbox (DB queue)");
+    sqlite::SqliteEventQueue::create_publisher(db_pool.clone(), &config.events).await
 }
 
 pub async fn create_channel(