Fix VirtViewer detection on Windows + manual path override

VirtViewer's installer folder name includes the version number
(e.g. "VirtViewer v11.0-256"), so the previous hardcoded path never
matched a real install. Now scans Program Files for any VirtViewer*
folder, and adds a Settings dialog (Windows only) to pick the
remote-viewer.exe path manually as a fallback.

src/renderer/vms.js

@@ -6,6 +6,9 @@ const emptyEl   = document.getElementById('emptyState');
 const errorEl   = document.getElementById('error');
 const noticeEl  = document.getElementById('notice');
 const refreshBtn = document.getElementById('refreshBtn');
+const settingsBtn = document.getElementById('settingsBtn');
+const settingsOverlay = document.getElementById('settingsOverlay');
+const viewerPathDisplay = document.getElementById('viewerPathDisplay');
 
 document.getElementById('logoutBtn').addEventListener('click', async () => {
   await api.proxmox.logout();
@@ -13,6 +16,42 @@ document.getElementById('logoutBtn').addEventListener('click', async () => {
 
 refreshBtn.addEventListener('click', () => loadVMs());
 
+// ── Settings (Windows only — VirtViewer's install folder name carries the
+//    version number, so auto-detection can miss non-standard installs) ──
+
+initSettings();
+
+async function initSettings() {
+  const platform = await api.settings.platform();
+  if (platform !== 'win32') return;
+
+  settingsBtn.classList.remove('hidden');
+  settingsBtn.addEventListener('click', openSettings);
+  document.getElementById('closeSettingsBtn').addEventListener('click', closeSettings);
+  document.getElementById('browseViewerBtn').addEventListener('click', async () => {
+    const chosen = await api.settings.browseViewerPath();
+    if (chosen) await refreshViewerPathDisplay();
+  });
+  document.getElementById('resetViewerBtn').addEventListener('click', async () => {
+    await api.settings.clearViewerPath();
+    await refreshViewerPathDisplay();
+  });
+}
+
+async function openSettings() {
+  await refreshViewerPathDisplay();
+  settingsOverlay.classList.remove('hidden');
+}
+
+function closeSettings() {
+  settingsOverlay.classList.add('hidden');
+}
+
+async function refreshViewerPathDisplay() {
+  const viewerPath = await api.settings.getViewerPath();
+  viewerPathDisplay.textContent = viewerPath || 'automatisch erkannt';
+}
+
 // ── Load on mount ─────────────────────────────────────────
 
 async function loadVMs() {