Smoke tests after Netlify deployment

Create a simple smoke test after deployment, it should check that something is rendered on the page - a screenshot could be just fine.

This guide seems to cover how to set it up between Github and Netlify: https://blog.termian.dev/posts/trigger-tests-github-actions/

I'm thinking of using Playwright for UI tests, might be a bit overkill for just this purpose, but we also have #175

Background:

I recently broke the build due to restructuring source files under a new directory `src` and also added the `src` directory in rollup config for the bundled source.

I forgot to update the latkatzombit.js path in index.html, so nothing was of course run and only the empty page was visually rendered.

Review index.html, the src layout, and the Rollup configuration first, then use the linked GitHub/Netlify setup guide and issue #175 to understand the intended deployment hook. Done means a post-deployment smoke test runs and verifies that the page renders, optionally with a screenshot, catching a broken script path such as latkatzombit.js.

Written by the indexing model from the issue text.