- add `make clean` and run it before `test-e2e` to avoid stale artifacts
- restore: do not hardcode `mysql` for --empty; use detected mariadb/mysql client
- e2e: improve subprocess error output for easier CI debugging
- e2e: adjust MariaDB readiness checks for socket-only root on MariaDB 11
- e2e: add `wait_for_mariadb_sql` and run SQL readiness checks for dedicated TCP user
- e2e: update MariaDB full/no-copy tests to use dedicated user over TCP and consistent credentials
https://chatgpt.com/share/694ecfb8-f8a8-800f-a1c9-a5f410d4ba02