Add theme selection element to settings.html

settings.html

@@ -160,6 +160,7 @@
     document.body.classList.toggle('sky-mode', isSky);
 
     // Elemente holen
+    const themeSelect       = document.getElementById('themeSelect');
     const cbSky       = document.getElementById('skymode');
     const cbSkip      = document.getElementById('skipPrompt');
     const thresholdInput = document.getElementById('intelligentCommitThresholdInput');