feat(tests): enhance product creation tests with dynamic SKUs

feat(tests): add integration tests for Product and Category

feat(liquibase): add product table creation changelog

feat(liquibase): add multi-schema migration support

test(mapper): add tests to ensure ID and SKU remain unchanged

feat(mapper): enhance merge methods and test coverage

feat(mapper): add merge methods for Category and Product

refactor(controller): improve service cohesion and exception handling

docs(next_actions): add roadmap for product service integration

refactor(controller): simplify exception handling in Category and Product controllers

feat(exception): add custom exceptions and global handler

feat(ui): update toolbar styling and content

refactor(routes): clean up routing configuration

feat(proxy): add shared proxy configuration for API integration

feat(ui): Implement product listing micro-frontend