Redo detail, study, utility and gate pages; fix admin live preview (CSP frame-src self) and preview every admin section; v2.38.0

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

server.js

@@ -102,7 +102,7 @@ app.use((_req, res, next) => {
       "font-src 'self' https://fonts.gstatic.com",
       "img-src 'self' data: https:",
       "media-src 'self' https:",
-      "frame-src https:",
+      "frame-src 'self' https:",
       "connect-src 'self' https:",
     ].join('; '),
   )