domain: add domain errors, events, and services module scaffold

crates/domain/tests/domain_tests.rs

@@ -1 +1,2 @@
+mod events;
 mod value_objects;

crates/domain/tests/events.rs

@@ -0,0 +1,14 @@
+use domain::events::DomainEvent;
+use domain::value_objects::{DateTimeStamp, SystemId};
+
+#[test]
+fn asset_ingested_serde_roundtrip() {
+    let event = DomainEvent::AssetIngested {
+        asset_id: SystemId::new(),
+        owner_user_id: SystemId::new(),
+        timestamp: DateTimeStamp::now(),
+    };
+    let json = serde_json::to_string(&event).unwrap();
+    let back: DomainEvent = serde_json::from_str(&json).unwrap();
+    assert!(matches!(back, DomainEvent::AssetIngested { .. }));
+}