domain: add cross-cutting value objects (SystemId, DateTimeStamp, Checksum, StructuredData)

crates/presentation/src/handlers/auth.rs

@@ -19,7 +19,7 @@ pub async fn register(
     ValidatedJson(req): ValidatedJson<RegisterRequest>,
 ) -> Result<(StatusCode, Json<AuthResponse>), AppError> {
     let user = state.register_uc.execute(&req.email, &req.password).await?;
-    let token = state.token_issuer.issue(&user.id, &user.role).await.map_err(AppError::from)?;
+    let token = state.token_issuer.issue(&user.id, "user").await.map_err(AppError::from)?;
     Ok((StatusCode::CREATED, Json(AuthResponse { token, user: UserResponse::from_domain(&user) })))
 }