feat: add diarization section to settings page

Adds a "Diarisierung" section with an enabled/disabled toggle,
HuggingFace token input, and a help link to pyannote/speaker-diarization-3.1.
loadConfig() and the save handler now persist diarization settings.

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

frontend/settings.js

@@ -58,6 +58,9 @@ async function loadConfig() {
   const ollamaUrl = (cfg.ollama && cfg.ollama.base_url) || 'http://localhost:11434';
   document.getElementById('ollama-url').value = ollamaUrl;
   await loadOllamaModels(ollamaUrl, cfg.ollama && cfg.ollama.model);
+  const diarCfg = cfg.diarization || {};
+  document.getElementById('diar-enabled').checked = !!diarCfg.enabled;
+  document.getElementById('diar-hf-token').value = diarCfg.hf_token || '';
 }
 
 document.getElementById('refresh-devices-btn').addEventListener('click', loadDevices);
@@ -98,6 +101,10 @@ document.getElementById('save-btn').addEventListener('click', async function() {
       base_url: document.getElementById('ollama-url').value,
       model: document.getElementById('ollama-model').value,
     },
+    diarization: {
+      enabled: document.getElementById('diar-enabled').checked,
+      hf_token: document.getElementById('diar-hf-token').value.trim(),
+    },
   };
   const r = await apiFetch('/config', { method: 'PUT', body: JSON.stringify(body) });
   if (r.ok) { showToast('Gespeichert'); } else { showToast('Fehler beim Speichern'); }