Sidebar: Menü ein-/ausklappbar (eingeklappt als Symbolleiste, Zustand wird gemerkt)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/renderer/app.js

@@ -154,6 +154,26 @@ $$('#sidebar .nav[data-view]').forEach((n) => n.addEventListener('click', () =>
   render();
 }));
 
+// ============================================================ Einklappbares Menü (Sidebar)
+(() => {
+  const KEY = 'mrterm.nav.collapsed';
+  const sb = $('#sidebar');
+  // Tooltips für die Symbolansicht
+  $$('#navMenu .nav').forEach((n) => { n.title = n.querySelector('span')?.textContent || ''; });
+  const apply = (collapsed) => {
+    sb.classList.toggle('nav-collapsed', collapsed);
+    $('#navToggle').title = collapsed ? 'Menü ausklappen' : 'Menü einklappen';
+  };
+  let collapsed = false;
+  try { collapsed = localStorage.getItem(KEY) === '1'; } catch {}
+  apply(collapsed);
+  $('#navToggle').onclick = () => {
+    collapsed = !collapsed;
+    apply(collapsed);
+    try { localStorage.setItem(KEY, collapsed ? '1' : '0'); } catch {}
+  };
+})();
+
 // ============================================================ Verzeichnisbaum (Sidebar)
 const TREE_KEY = 'mrterm.tree.open';
 const treeOpen = new Set((() => { try { return JSON.parse(localStorage.getItem(TREE_KEY) || '[]'); } catch { return []; } })());