add complete button to signing form header

app/views/submit_form/show.html.erb

@@ -22,6 +22,7 @@
             <%= @submitter.submission.name || @submitter.submission.template.name %>
           </h1>
           <div class="flex items-center space-x-2" style="margin-left: 20px; flex-shrink: 0">
+            <span id="complete_button_container"></span>
             <% if @form_configs[:with_delegate] %>
               <modal-button data-target="<%= delegate_modal_id = SecureRandom.uuid %>">
                 <button id="delegate_button" type="button" class="btn btn-sm !px-5"><%= t(:delegate) %></button>
@@ -65,6 +66,7 @@
           </div>
         </header>
         <scroll-buttons inert class="fixed right-5 top-2 hidden md:flex gap-1 z-50 ease-in-out opacity-0 -translate-y-10">
+          <span id="complete_button_container_mobile"></span>
           <% if @form_configs[:with_delegate] %>
             <modal-button data-target="<%= delegate_modal_id %>">
               <button id="delegate_button_mobile" type="button" class="btn btn-sm px-0" aria-label="<%= t(:delegate) %>">