Add Cypress to test stack

[jessicamcinchak]

We introduced Vitest for unit testing in #139

But, especially for the web map component, it would be valuable to additionally add tests for expected interactions (like zooming, drawing, modifying, etc) in the browser, which Cypress would enable.

Links:

• https://vitest.dev/guide/comparisons.html#cypress
• This video plus others in the series look like a helpful starter