Migrate an application database to PostgreSQL with minimal risk and a clear rollback plan. The project requires careful mapping of data types, indexes, relationships, and application queries. We expect a test migration, validation report, production runbook, and support during the final cutover. The successful freelancer will be expected to work independently, share progress at agreed checkpoints, and raise questions early when a requirement needs clarification. All submitted work should be original, well organized, and ready for practical use after reasonable review.