feat: review pull requests from update triage (Closes #775)

frontend/index.html

@@ -814,6 +814,7 @@
     <div class="update-decision-bar" aria-label="Update decisions">
       <button id="keep-update-unread" type="button" aria-label="Keep unread and open next update">Keep unread</button>
       <button id="mark-update-read-next" type="button" aria-label="Mark read and open next update">Mark read</button>
+      <button id="review-update-now" type="button" hidden>Review now</button>
       <button id="focus-update-reply" type="button">Reply</button>
       <button id="toggle-update-more" type="button" aria-expanded="false">More</button>
     </div>
@@ -1088,6 +1089,7 @@
 <script src="static/mobile-work-entry.js"></script>
 <script src="static/mobile-queue-launcher.js"></script>
 <script src="static/update-triage-session.js"></script>
+<script src="static/update-review-handoff.js"></script>
 <script src="static/update-read-position.js"></script>
 <script src="static/update-triage-launcher.js"></script>
 <script src="static/update-triage-gesture.js"></script>