Remove unused jQuery UI + dead autocomplete.css (#1288)

jQuery UI (JS + theme CSS) was loaded on index, awards, and publications
but had zero widget API calls (.autocomplete/.tabs/.datepicker/...) and zero
ui-* classes in any markup — those pages use tocbot for their TOC, not
jQuery UI. autocomplete.css (global, in base.html) only styled the jQuery UI
autocomplete widget that was removed long ago (files date to 2022).

Removes ~61KB of dead front-end assets and three <script>/<link> includes,
shrinking the surface for the Track A jQuery/Bootstrap-JS removal (#1253).
No functional or visual change: all affected pages still return 200 and
render identically (verified via smoke test); tocbot TOCs unaffected.

Deletes:
- website/static/website/js/jquery-ui.min.js
- website/static/website/css/jquery-ui.min.css
- website/static/website/css/jquery-ui.theme.min.css
- website/static/website/css/autocomplete.css

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: jonfroehlich