Merge the drill lane fix and the rate-gate sample size into staging

index.html conflicted only on the cache-buster: staging was at 276 and the
branch at 275, so the merge takes 277 — a merge that reuses either number
leaves phones on the old build.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

index.html

@@ -659,6 +659,6 @@ if (location.hostname !== 'splatter-tennis.wuwi.one') {
     </div>
   </div>
 </div>
-<script type="module" src="src/main.js?v=276"></script>
+<script type="module" src="src/main.js?v=277"></script>
 </body>
 </html>