ux: "Did you mean" suggestions in the empty search state, reusing the 404 page's closest-match logic #109

Why it matters
A typo ("quaternious", "kenny") shows an empty result list and a "Clear filters" button. The 404 page already solves this: it suggests the closest entries by name. Zero-result searches are the moment a visitor leaves, and the fix is a function call away.

Evidence

• site/lib/search.mjs exports closestEntries, used by site/public/not-found.js.
• site/public/app.js renders #empty-state without suggestions.

Suggested approach
When results are empty and the query is non-empty, call closestEntries(query, entries, 5) and render "Did you mean: Quaternius, ..." as buttons that set the search box. Add a test in lib.test.mjs for a misspelt publisher.

Done when
A misspelt search shows up to five clickable suggestions, and clicking one runs that search.