- Added ?v=20260502 query param to all <script src=...> and <link> tags
- Added Cache-Control: no-cache, no-store, must-revalidate to index route
- Added <meta> cache-control tags in HTML head for extra coverage
- This ensures the browser always fetches fresh HTML/JS/CSS after deploy,
preventing the old loadLastPrompt() from running against new HTML
(which would crash since #prompt-cat-info no longer exists)