Add & Improve JSDocs

## Goal

The goal of this ticket is to investigate and expand the project's JSDoc coverage to improve in-code documentation and make the codebase easier to understand and maintain.

## Bonus

Explore options for extracting and rendering the JSDocs as a static documentation site.

There are tools available that can generate Markdown from JSDoc comments, making it possible to use a GitHub Action to build and deploy the documentation automatically.

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## List of APIs

TODO: Create a checkbox list of all APIs and check them when JSDocs are added or improved.