All tables belong to `baiyue_iam`, accessed only by `iam-service`. `auth-service` owns credentials and tokens in `baiyue_auth`. `iam_user.auth_user_id` is a logical cross-database reference; no cross-database foreign keys are used. Every merchant query must constrain `tenant_id`. Platform scope uses `tenant_id=0` and `app_code=PLATFORM`; merchant scope uses `app_code=MERCHANT`.
Merge the packages under `src/main/java` into `D:/baiyue/iam/src/main/java`; execute `db/baiyue_iam.sql`. The skeleton targets Java 17, Spring Boot 3.2 and MyBatis-Plus 3.5.7, returning the existing `ApiResponse` envelope.