feat: make mobile task overlays back-safe (#315)

frontend/index.html

@@ -524,6 +524,7 @@
 <script src="static/pull-sheet.js"></script>
 <script src="static/review-sheet.js"></script>
 <script src="static/work-route.js"></script>
+<script src="static/task-overlay-history.js"></script>
 <script src="static/context-poller.js"></script>
 <script src="static/mobile-task-dock.js"></script>
 <script src="static/mobile-launch.js"></script>