Set up docs site #28

The Image Embedding Explorer tutorial currently lives in the workshop repo (conference-tutorials-2026).

We should setup a site here and copy the tutorial from the workshop site:

• Set up a docs site for emb-explorer Zensical
• Port the Image Embedding Explorer tutorial from conference-tutorials-2026 to docs/ in this repo. Copy over the workshop screenshots (docs/assets/finches/*.png)
• Add GitHub Action to build and deploy to GitHub Pages on push to main
• Link the docs site from the README