Never cache HTML (no-store) so wallet browsers can't serve stale pages

Trust's in-app browser was serving a cached pre-fix HTML page that pointed at
old JS, re-triggering the numeric-chainId crash even after the fix shipped.
Switch HTML from no-cache to no-store so every load fetches the current page and
its current asset versions. Versioned assets still cache for an hour.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

server.js

@@ -177,7 +177,10 @@ function sendFile(res, file) {
     if (err) { res.writeHead(404, baseHeaders({ 'Content-Type': 'text/plain' })); return res.end('Not found'); }
     const ext = path.extname(file).toLowerCase();
     res.writeHead(200, baseHeaders({ 'Content-Type': MIME[ext] || 'application/octet-stream',
-      'Cache-Control': ext === '.html' ? 'no-cache' : 'public, max-age=3600' }));
+      // HTML is never stored (so a fresh load always gets the current asset
+      // versions — aggressive in-app wallet browsers were serving stale pages
+      // that pointed at old, since-fixed JS); versioned assets cache for an hour.
+      'Cache-Control': ext === '.html' ? 'no-store, must-revalidate' : 'public, max-age=3600' }));
     res.end(data);
   });
 }