feat: update action button icon from ellipsis to more-vertical and fix icon rendering scope

- Change action button icon from 'ellipsis' to 'more-vertical' for better visual consistency
- Update safeCreateIcons call to render all icons globally instead of scoping to button element

frontend/app.js

@@ -4749,7 +4749,7 @@
     button.className = "tree-item-action-btn";
     button.setAttribute("aria-label", "Afficher le menu d’actions");
     button.setAttribute("title", "Actions");
-    const iconEl = icon("ellipsis", 16);
+    const iconEl = icon("more-vertical", 16);
     button.appendChild(iconEl);
     button.addEventListener("click", (e) => {
       e.preventDefault();
@@ -4760,7 +4760,7 @@
     itemEl.appendChild(button);
     // Ensure Lucide icons are rendered for the button
     setTimeout(() => {
-      safeCreateIcons(button);
+      safeCreateIcons();
     }, 0);
   }