* test: add accessibility test utilities
* refactor(tests): replace polling with Promise chain for axe test queue management
* test: add a11y test for components demo
* feat: add a11y test utils
* test: add a11y test for components demo
* test: add a11y test for components demo
* chore: remove unnecessary code
* feat: add polyfill for test environment
* test: add a11y test for components demo
* test: add a11y test for components demo
* chore: adjust code style
