feat(infra): transactional outbox — OutboxWriter port, PgOutboxWriter, OutboxRelay, TestOutbox; update create_thought + delete_thought

crates/domain/src/ports.rs

@@ -44,6 +44,11 @@ pub trait EventConsumer: Send + Sync {
     fn consume(&self) -> futures::stream::BoxStream<'_, Result<EventEnvelope, DomainError>>;
 }
 
+#[async_trait]
+pub trait OutboxWriter: Send + Sync {
+    async fn append(&self, event: &DomainEvent) -> Result<(), DomainError>;
+}
+
 #[async_trait]
 pub trait UserReader: Send + Sync {
     async fn find_by_id(&self, id: &UserId) -> Result<Option<User>, DomainError>;

crates/domain/src/testing.rs

@@ -937,6 +937,33 @@ impl EventPublisher for NoOpEventPublisher {
     }
 }
 
+#[derive(Default, Clone)]
+pub struct TestOutbox {
+    pub entries: Arc<Mutex<Vec<DomainEvent>>>,
+}
+
+impl TestOutbox {
+    pub fn staged(&self) -> Vec<DomainEvent> {
+        self.entries.lock().unwrap().clone()
+    }
+}
+
+#[async_trait]
+impl OutboxWriter for TestOutbox {
+    async fn append(&self, event: &DomainEvent) -> Result<(), DomainError> {
+        self.entries.lock().unwrap().push(event.clone());
+        Ok(())
+    }
+}
+
+pub struct NoOpOutboxWriter;
+#[async_trait]
+impl OutboxWriter for NoOpOutboxWriter {
+    async fn append(&self, _e: &DomainEvent) -> Result<(), DomainError> {
+        Ok(())
+    }
+}
+
 #[cfg(test)]
 mod ap_repo_tests {
     use super::*;