feat: event store — persist domain events to Postgres event_log table via composite publisher

crates/domain/src/common/ports.rs

@@ -1,5 +1,6 @@
 use crate::common::errors::DomainError;
 use crate::common::events::{DomainEvent, EventEnvelope};
+use crate::common::value_objects::SystemId;
 use async_trait::async_trait;
 use futures::stream::BoxStream;
 
@@ -11,3 +12,9 @@ pub trait EventPublisher: Send + Sync {
 pub trait EventConsumer: Send + Sync {
     fn consume(&self) -> BoxStream<'_, Result<EventEnvelope, DomainError>>;
 }
+
+#[async_trait]
+pub trait EventStore: Send + Sync {
+    async fn append(&self, event: &DomainEvent) -> Result<(), DomainError>;
+    async fn query_by_aggregate(&self, aggregate_id: &SystemId) -> Result<Vec<DomainEvent>, DomainError>;
+}