domain: add Sharing entities and ports (ShareScope, ShareTarget, ShareLink, InviteCode, VisibilityFilter)

crates/domain/tests/entities/share_link.rs

@@ -0,0 +1,25 @@
+use domain::entities::{LinkAccessLevel, ShareLink};
+use domain::value_objects::SystemId;
+
+#[test]
+fn new_link_is_valid() {
+    let link = ShareLink::new(SystemId::new(), "tok123", LinkAccessLevel::ViewOnly);
+    assert!(link.is_valid());
+    assert_eq!(link.use_count, 0);
+}
+
+#[test]
+fn deactivated_invalid() {
+    let mut link = ShareLink::new(SystemId::new(), "tok123", LinkAccessLevel::ViewOnly);
+    link.deactivate();
+    assert!(!link.is_valid());
+}
+
+#[test]
+fn max_uses_exhausted() {
+    let mut link = ShareLink::new(SystemId::new(), "tok123", LinkAccessLevel::ViewOnly);
+    link.max_uses = Some(2);
+    link.record_use();
+    link.record_use();
+    assert!(!link.is_valid());
+}