Add responsive carousel direction controls

[alexstandiford]

Summary

• Add responsive carousel direction attributes for desktop, tablet, and mobile.
• Add optional responsive carousel height and fixed slide height settings so top-to-bottom Splide carousels can be configured without custom JavaScript.
• Extend carousel padding to support top/bottom padding for vertical tracks while preserving left/right behavior for horizontal tracks.
• Add responsive AutoScroll enablement controls so a carousel can auto-scroll vertically on desktop and fall back to normal horizontal drag on tablet/mobile.
• Preserve vertical Splide list direction after WordPress layout styles are applied.

Validation

• npm run build passes.
• npm run lint:js currently reports existing lint/prettier issues on upstream main, including files outside this change.
• npm run lint:css currently reports existing stylelint issues on upstream main in src/blocks/carousel/view.css.

[alexstandiford]

Closing this fork-backed draft in favor of #23, which uses the same changes from a branch on humanmade/hm-carousel-block now that direct repository access is available.