[TB] Research ability to dynamically update UI with only JSON token generator

## Problem/Concern

This issue is related to #888 and the other issues surrounding our decision to have a "single source of truth" JSON token generator rather than continuing to support both CSS and JSON generation. If we no longer update CSS variables currently in use by the application as the user changes values in their design system, then can we still achieve this dynamic user experience?

Among the things to look at:
- [ ] Can StyleDictionary run in a browser?
- [ ] Would it need to be manually triggered (e.g. on a save)? Currently UI dynamically changes as user changes values in design system.
- [ ] How would a Netlify or Docker user retrieve the the CSS representing the design system they built in Theme Builder?

## Proposed Solution

Review related issue #888 and the single-source-of-truth JSON token generator decision first. Investigate whether StyleDictionary can run in a browser, how generation would be triggered as design values change, and how Netlify or Docker users would retrieve CSS. Done means documenting a viable approach for dynamic updates and CSS retrieval.

Written by the indexing model from the issue text.