public buildConnectionString() as String:
Builds the driver URL consumed by klyn.databases.sql.DriverManager.
Klyn SQL drivers use scheme URLs such as mariadb://host:3306/db; the historical JDBC prefix is intentionally not emitted.
config = DatabaseConfig("mariadb", "localhost", 3306, "klyn", "klyn", "secret")
assert config.buildConnectionString() == "mariadb://localhost:3306/klyn"