feat: complete delegated parent task from Filed review (Closes #923)

frontend/index.html

@@ -600,7 +600,10 @@
     <div id="issue-sheet-status" class="small" aria-live="polite">Choose an issue.</div>
     <section class="completed-filed-actions" id="completed-filed-actions" aria-label="Completed Filed review" hidden>
       <span id="completed-filed-progress" role="status" aria-live="polite">Completed Filed issue ready for review.</span>
-      <button id="acknowledge-completed-filed" type="button">Acknowledge &amp; next</button>
+      <div class="completed-filed-buttons">
+        <button id="complete-parent-and-acknowledge" type="button" hidden>Complete parent step &amp; acknowledge</button>
+        <button id="acknowledge-completed-filed" type="button">Acknowledge &amp; next</button>
+      </div>
     </section>
     <button class="issue-retry" id="retry-issue-load" type="button" hidden>Reload latest issue</button>
     <div class="row"><span id="issue-labels"></span><span class="small" id="issue-assignees"></span></div>