Feature: Konfig-Export/Import im Web UI (Einstellungen-Tab)

- GET /api/export-config → JSON-Download mit allen Geräten + MQTT (ohne Passwort)
- POST /api/import-config → Validierung + Übernahme + automatischer Neustart
- Einstellungen-Tab: Exportieren-Button + Importieren-Dateiauswahl
- btn-secondary CSS-Klasse hinzugefügt

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

haos-addon/src/web/index.html

@@ -91,6 +91,8 @@
   .btn-danger:hover { background: rgba(248,81,73,.1); }
   .btn-primary { background: var(--accent); color: #000; border-color: var(--accent); font-weight: 700; }
   .btn-primary:hover { opacity: .85; }
+  .btn-secondary { color: var(--blue); border-color: var(--blue); }
+  .btn-secondary:hover { background: rgba(88,166,255,.1); }
   .inv-card-meta { font-size: 12px; color: var(--text-dim); line-height: 1.7; }
   .add-btn { display: flex; align-items: center; justify-content: center; gap: 8px;
     padding: 20px; background: var(--surface); border: 2px dashed var(--border);
@@ -189,6 +191,19 @@
         <input type="password" id="cfg-mqtt-pass" placeholder="leer = unverändert"></div>
       <button class="btn btn-primary" onclick="saveMqtt()">Speichern & Neu starten</button>
     </div>
+
+    <div class="settings-section">
+      <h3>Konfiguration sichern</h3>
+      <p style="color:var(--text-dim);font-size:.85rem;margin:0 0 .75rem">Alle Geräte und MQTT-Einstellungen als JSON exportieren und bei einer Neuinstallation wieder einlesen.</p>
+      <div style="display:flex;gap:.5rem;flex-wrap:wrap">
+        <button class="btn btn-secondary" onclick="exportConfig()">&#8659; Exportieren</button>
+        <label class="btn btn-secondary" style="cursor:pointer">
+          &#8657; Importieren
+          <input type="file" id="import-file-input" accept=".json" style="display:none" onchange="importConfig(this)">
+        </label>
+      </div>
+      <div id="import-result" style="margin-top:.5rem;font-size:.85rem"></div>
+    </div>
   </div>
 </main>
 
@@ -529,6 +544,37 @@ async function saveMqtt() {
   }
 }
 
+// ── Export / Import ───────────────────────────────────────────
+
+function exportConfig() {
+  window.location.href = api("api/export-config");
+}
+
+async function importConfig(input) {
+  const file = input.files[0];
+  if (!file) return;
+  const resultEl = document.getElementById("import-result");
+  resultEl.textContent = "Wird geladen…";
+  resultEl.style.color = "var(--text-dim)";
+  try {
+    const text = await file.text();
+    const data = JSON.parse(text);
+    const res = await fetchJSON(api("api/import-config"), {
+      method: "POST", headers: {"Content-Type": "application/json"},
+      body: JSON.stringify(data),
+    });
+    resultEl.textContent = `✓ ${res.inverters} Gerät(e) importiert. Neustart läuft…`;
+    resultEl.style.color = "var(--green)";
+    showToast(`${res.inverters} Gerät(e) importiert`, "ok");
+    setTimeout(() => { loadSettings(); loadInverters(); }, 3000);
+  } catch(e) {
+    resultEl.textContent = `Fehler: ${e.message}`;
+    resultEl.style.color = "var(--red)";
+    showToast("Import fehlgeschlagen", "err");
+  }
+  input.value = "";
+}
+
 // ── Init ──────────────────────────────────────────────────────
 
 (async () => {