feat(backup): download the full backup as ZIP

GET /export?format=zip streams the JSON backup compressed (plain JSON stays
the API default). The MindSift import recognises the backup ZIP next to the
plain JSON and the Markdown archive.

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

frontend/src/features/settings/UserSettingsView.tsx

@@ -375,12 +375,16 @@ export const UserSettingsView: React.FC<UserSettingsViewProps> = ({
     window.setTimeout(() => URL.revokeObjectURL(url), 10000);
   };
 
+  const [exportingBackup, setExportingBackup] = useState(false);
   const handleExportData = async () => {
-    const data = await api.exportAll();
-    const blob = new Blob([JSON.stringify(data, null, 2)], {
-      type: 'application/json;charset=utf-8',
-    });
-    saveBlob(blob, `mindsift-backup-${new Date().toISOString().slice(0, 10)}.json`);
+    setExportingBackup(true);
+    try {
+      saveBlob(await api.exportBackupZip(), `mindsift-backup-${new Date().toISOString().slice(0, 10)}.zip`);
+    } catch (err: any) {
+      setVaultError(err.message || 'Backup fehlgeschlagen');
+    } finally {
+      setExportingBackup(false);
+    }
   };
 
   const [exportingVault, setExportingVault] = useState(false);
@@ -1238,18 +1242,19 @@ export const UserSettingsView: React.FC<UserSettingsViewProps> = ({
               {/* Full Data Backup */}
               <div className="pt-4 border-t border-border flex flex-col sm:flex-row sm:items-center justify-between gap-3">
                 <div>
-                  <h3 className="font-bold text-main">Vollständiger Daten-Export (JSON Backup)</h3>
+                  <h3 className="font-bold text-main">Vollständiges Backup (.zip)</h3>
                   <p className="text-muted text-[11px]">
-                    Lädt alle deine Gedanken, Aufgaben, Markdown-Dokumente und Listen als portable
-                    JSON-Datei herunter.
+                    Alle deine Gedanken, Aufgaben, Notizen und Listen als JSON, gepackt in eine ZIP-Datei. Über
+                    „MindSift-Daten importieren“ lässt es sich vollständig zurückspielen.
                   </p>
                 </div>
                 <button
                   onClick={handleExportData}
-                  className="btn-action h-9 px-4 text-xs flex items-center gap-2 flex-shrink-0"
+                  disabled={exportingBackup}
+                  className="btn-action h-11 sm:h-9 px-4 text-xs flex items-center justify-center gap-2 flex-shrink-0 disabled:opacity-50"
                 >
                   <Download className="w-3.5 h-3.5 text-accent" />
-                  <span>Backup herunterladen</span>
+                  <span>{exportingBackup ? 'Wird erstellt…' : 'Backup herunterladen'}</span>
                 </button>
               </div>
 

frontend/src/lib/api.ts

@@ -135,6 +135,14 @@ export const setCurrentSharingMode = (mode: SharingMode) => {
 };
 export const isSharingDisabled = () => currentSharingMode === 'private';
 
+// Authenticated binary download (archives); no JSON parsing and no request timeout
+async function downloadBlob(path: string): Promise<Blob> {
+  const token = getToken();
+  const res = await fetch(path, { headers: token ? { Authorization: `Bearer ${token}` } : {}, cache: 'no-store' });
+  if (!res.ok) throw new Error(`Download fehlgeschlagen (HTTP ${res.status})`);
+  return res.blob();
+}
+
 export const api = {
   // --- AUTH, FIRST-BOOT SETUP & SETTINGS ---
   async getAuthStatus(): Promise<AuthStatus> {
@@ -1093,15 +1101,14 @@ export const api = {
     return data as ImportSummary;
   },
 
+  // Full backup (all data as JSON) packed into a ZIP; restorable via importData('mindsift', …)
+  async exportBackupZip(): Promise<Blob> {
+    return downloadBlob('/api/v1/export?format=zip');
+  },
+
   // Obsidian-compatible ZIP of the workspace; binary and possibly large, so no JSON helper and no timeout
   async exportMarkdownVault(): Promise<Blob> {
-    const token = getToken();
-    const res = await fetch('/api/v1/export/markdown', {
-      headers: token ? { Authorization: `Bearer ${token}` } : {},
-      cache: 'no-store',
-    });
-    if (!res.ok) throw new Error(`Export fehlgeschlagen (HTTP ${res.status})`);
-    return res.blob();
+    return downloadBlob('/api/v1/export/markdown');
   },
 };