domain: add RefreshSession model + repository port

crates/domain/src/models/refresh_session.rs

@@ -0,0 +1,13 @@
+use chrono::{DateTime, Utc};
+use uuid::Uuid;
+
+use crate::value_objects::UserId;
+
+#[derive(Clone, Debug)]
+pub struct RefreshSession {
+    pub id: Uuid,
+    pub user_id: UserId,
+    pub token: String,
+    pub expires_at: DateTime<Utc>,
+    pub created_at: DateTime<Utc>,
+}