[sabinem]

Hackathon owners and participants can now read how the platform works

User Story: As someone running a hackathon, I want to look up what a page or a checkbox does, so that I don't open voting by accident or leave participants unable to see their own team. Until now there was no documentation at all. The Settings page in particular was confusing: moving to the next phase opens nothing, and the effect of each checkbox was easy to misread.

Now there is a documentation site, published to GitHub Pages from main. It has a guide for owners and one for participants. Every entry in a hackathon's menu has its own page with a screenshot. The Settings page goes through the checkboxes step by step and links each one to the pages it affects.

• Its own component in docs/: Sphinx with Markdown and the Furo theme. just docs::build builds it, and any warning, such as a broken link, fails the build. just docs::serve shows a live preview.
• Every page says which version it describes. The published site follows main, the same version dev runs, while prod can run an older release.
• just docs::screenshots retakes screenshots on demand from the local stack, with seeded data. It ends by listing which images changed, so you know which pages to reread. Sidebar links now carry data-nav-id for the script to click.
• CI builds the docs on every PR and publishes them from main. The Sphinx runner now fails on warnings and installs from the lock file on every run.

Deliberately left out:

• Links to the docs from inside the app (Help in the top bar, "How this works" on Settings). They're a separate PR, once the site is live.
• Docs for each release. The site shows only the latest development version for now, and says so on every page.
• Topic pages that span several screens, such as "running a vote from start to finish".

Next step:

• The pages beyond Settings are short so far: a title, one sentence and a screenshot.

Verified:

• The docs build
• The Pages job has never run. It needs Pages turned on and a first merge to main.