[glebfox]

The site loads its stylesheets and scripts from fixed URLs such as _/css/site.css. The IntelliJ IDEA built-in browser keeps the copies it cached, so after a release it shows new pages with old styles until the user runs Invalidate Caches.

Now each UI stylesheet and script URL carries a hash of the file content, for example _/css/site.css?v=2eca4c9a57. A changed file gets a new URL, and the browser loads it.

• ui/asset-hash-extension.js is an Antora extension. It hashes every CSS and JS file of the UI (ours, the bundle's and the Lunr extension's) and registers the asset Handlebars helper.
• head-styles.hbs and footer-scripts.hbs reference the files as {{{asset 'css/site.css'}}} instead of {{{uiRootPath}}}/css/site.css. The helper fails the build when the UI has no such file.
• Both playbooks register the extension after the Lunr extension. A playbook without the extension fails with Missing helper: "asset", so a production playbook kept outside this repository needs the same line.
• ui/README.md and AGENTS.md describe the helper.

search-index.js is not a UI file and stays without a hash. The hashes work only when the browser requests fresh HTML, so the server should send the pages with Cache-Control: no-cache.

Checked: the site builds, all 13 hashes in the HTML match the published files, and node tools/ui-audit.mjs passes.