Fix admin navigation sticky unassigned pool

TODO.md

@@ -537,6 +537,7 @@ Current state on `experimental-feedback-system` as of 2026-06-18: the core feedb
 
 ## Done
 
+- 2026-06-18: Emergency patched `/admin/navigation` so the Unassigned items pool stays sticky while editing sections on desktop, and aligned Save navigation / Reset to default actions in a shared horizontal Lumi button group.
 - 2026-06-18: Removed feedback conversion actions from the experimental feedback system, added Finalize & Close/Reopen/Delete admin actions, made delete hard-remove feedback records/comments/notes/history/screenshots, kept admin feedback rows collapsed by default, and replaced browser tab capture screenshots with upload/clipboard-paste attachments.
 - 2026-06-18: Fixed experimental feedback review buttons to use the stable save endpoint for Finalize & Close/Reopen and added a reusable Lumi `button-group` utility, including the `.field.button-group` specificity case, so review buttons align horizontally.
 - 2026-06-18: Moved feedback screenshot guidance above Description, centered feedback screenshot/form action rows, and moved feedback modal sizing overrides into the later-loaded Lumi component layer so generic `.modal` styles no longer win.

src/web/views/admin-navigation.ejs

@@ -24,6 +24,12 @@
     border-radius: 16px;
     padding: 1rem;
   }
+  .nav-actions {
+    margin-top: 1.5rem;
+  }
+  .nav-actions .inline-form {
+    margin: 0;
+  }
   .nav-section-list {
     display: flex;
     flex-direction: column;
@@ -96,6 +102,15 @@
   .nav-toolbar .button {
     white-space: nowrap;
   }
+  @media (min-width: 901px) {
+    .nav-pool-card {
+      position: sticky;
+      top: 1rem;
+      align-self: start;
+      max-height: calc(100vh - 2rem);
+      overflow: auto;
+    }
+  }
   @media (max-width: 900px) {
     .nav-builder-body {
       grid-template-columns: 1fr;
@@ -189,11 +204,13 @@
       </div>
     </div>
 
-    <button type="submit" class="button">Save navigation</button>
   </form>
+  <div class="button-group centered nav-actions">
+    <button type="submit" form="nav-form" class="button">Save navigation</button>
     <form method="post" action="/admin/navigation/reset" class="inline-form" data-confirm-mode="modal" data-confirm-text="Replace the current navigation layout with Lumi's default structure?">
       <button type="submit" class="button subtle">Reset to default</button>
     </form>
+  </div>
 </section>
 
 <script id="nav-items-data" type="application/json"><%- navItemsJson %></script>