Add @EnableJdbcJobRepository alongside @EnableBatchProcessing

In Spring Batch 6, @EnableBatchProcessing no longer configures a JDBC-based JobRepository on its own: the JDBC store configuration moved to a new @EnableJdbcJobRepository annotation, and a bare @EnableBatchProcessing now registers an in-memory ResourcelessJobRepository. This recipe adds @EnableJdbcJobRepository next to every @EnableBatchProcessing so JDBC-backed persistence is preserved, moving the JDBC-specific attributes (dataSourceRef, tablePrefix, etc.) to the new annotation, copying transactionManagerRef to it (kept on @EnableBatchProcessing as well), converting isolationLevelForCreate from its Spring Batch 5 String form to the Isolation enum, and dropping the removed lobHandlerRef attribute. Classes that already declare @EnableJdbcJobRepository or @EnableMongoJobRepository, and programmatic DefaultBatchConfiguration subclasses, are left unchanged. A non-literal isolationLevelForCreate value is left in place for manual migration.