feat: Enable profiling for Spotlight itself (#720)

Author: BYK

packages/overlay/src/lib/instrumentation.ts

@@ -28,6 +28,7 @@ export default function initSentry(initialTab: string, options: Sentry.BrowserOp
       matchRoutes,
     }),
     Sentry.replayIntegration(),
+    Sentry.browserProfilingIntegration(),
   ];
   const hash = document.location.hash.slice(1);
   if (hash.startsWith('spotlight')) {

packages/sidecar/src/main.ts

@@ -229,7 +229,11 @@ const fileServer = (filesToServe: Record<string, Buffer>) => {
     if (!Object.hasOwn(filesToServe, filePath)) {
       error404(req, res);
     } else {
-      res.writeHead(200, { 'Content-Type': contentType });
+      res.writeHead(200, {
+        // Enable profiling in browser
+        'Document-Policy': 'js-profiling,',
+        'Content-Type': contentType,
+      });
       res.end(filesToServe[filePath]);
     }
   };