refactor(view-transitions): zentralen withViewTransition-Helper in state.js, Duplikate entfernt

src/js/bookmark-import.js

@@ -4,20 +4,6 @@
    via chrome.bookmarks.getTree() / browser.bookmarks.getTree()
    ============================================= */
 
-/**
- * Fuehrt eine DOM-Mutation mit nativem View-Transition-Fade aus.
- * Feature-Detection-Fallback (Firefox < 144): instant.
- * reduced-motion kappt das Fade ueber den ungeschichteten @media-Block.
- * @param {Function} mutate - synchrone DOM-Mutation
- */
-function bmImportViewTransition(mutate) {
-  if (document.startViewTransition) {
-    document.startViewTransition(mutate);
-  } else {
-    mutate();
-  }
-}
-
 const BrowserBookmarkImport = {
 
   /** Initialisiert den Import-Button */
@@ -211,14 +197,14 @@ const BrowserBookmarkImport = {
     document.body.appendChild(overlay);
 
     // View-Transition-Fade
-    bmImportViewTransition(() => overlay.classList.add('active'));
+    withViewTransition(() => overlay.classList.add('active'));
   },
 
   /** Schliesst das Modal */
   _closeModal() {
     const overlay = document.getElementById('bmImportOverlay');
     if (!overlay) return;
-    bmImportViewTransition(() => {
+    withViewTransition(() => {
       overlay.classList.remove('active');
       overlay.remove();
     });