domain: add Media Catalog entities (Asset, Metadata, Stack, Derivative, Duplicate)

crates/domain/tests/entities/derivative_asset.rs

@@ -0,0 +1,20 @@
+use domain::entities::{DerivativeAsset, DerivativeProfile, GenerationStatus};
+use domain::value_objects::SystemId;
+
+#[test]
+fn lifecycle() {
+    let mut d = DerivativeAsset::new_pending(
+        SystemId::new(),
+        DerivativeProfile::ThumbnailSquare,
+        "/thumbs/abc.webp",
+    );
+    assert_eq!(d.generation_status, GenerationStatus::Pending);
+    assert_eq!(d.file_size, 0);
+    assert_eq!(d.dimensions, (0, 0));
+
+    d.mark_ready("image/webp", 4096, (256, 256));
+    assert_eq!(d.generation_status, GenerationStatus::Ready);
+    assert_eq!(d.mime_type, "image/webp");
+    assert_eq!(d.file_size, 4096);
+    assert_eq!(d.dimensions, (256, 256));
+}