feat: event infrastructure — payload, transport, NATS adapter

- EventPublisher now takes &DomainEvent (11 call sites + 3 impls updated)
- EventEnvelope + EventConsumer port in domain
- event-payload: serializable DomainEvent mirror with subject routing
- event-transport: generic Transport/MessageSource traits, publisher/consumer adapters
- adapters-nats: JetStream publish + durable pull consumer

crates/application/src/processing/commands/execute_pipeline.rs

@@ -77,7 +77,7 @@ impl ExecutePipelineHandler {
                 self.job_repo.save(&job).await?;
                 self.update_batch_on_complete(&job).await?;
                 self.event_pub
-                    .publish(DomainEvent::JobCompleted {
+                    .publish(&DomainEvent::JobCompleted {
                         job_id: job.job_id,
                         timestamp: DateTimeStamp::now(),
                     })
@@ -89,7 +89,7 @@ impl ExecutePipelineHandler {
                 self.job_repo.save(&job).await?;
                 self.update_batch_on_fail(&job).await?;
                 self.event_pub
-                    .publish(DomainEvent::JobFailed {
+                    .publish(&DomainEvent::JobFailed {
                         job_id: job.job_id,
                         error: error_msg,
                         timestamp: DateTimeStamp::now(),