Refactor GUI rendering and align RTA axis

www/ui/changelog.js

@@ -0,0 +1,30 @@
+let loadPromise = null;
+
+export function setupLazyChangelog(details, content) {
+  if (!details || !content || details.dataset.bound === '1') return;
+  details.dataset.bound = '1';
+
+  const load = async () => {
+    if (content.dataset.loaded === '1') return;
+    if (!loadPromise) {
+      loadPromise = fetch('./changelog.html', { cache: 'no-cache' })
+        .then((response) => {
+          if (!response.ok) throw new Error(`HTTP ${response.status}`);
+          return response.text();
+        });
+    }
+    try {
+      content.innerHTML = await loadPromise;
+      content.dataset.loaded = '1';
+    } catch (error) {
+      loadPromise = null;
+      content.textContent = 'Versionsverlauf konnte nicht geladen werden.';
+      console.warn('Changelog load error:', error);
+    }
+  };
+
+  details.addEventListener('toggle', () => {
+    if (details.open) void load();
+  });
+  if (details.open) void load();
+}