fix(version): Sidebar-Copyright wird jetzt auch aus version.js befuellt

frontend/js/calendar.js

@@ -14,6 +14,8 @@ document.title = `Calendarr ${APP_VERSION}`;
 document.addEventListener('DOMContentLoaded', () => {
   const imp = document.getElementById('impressum-version');
   if (imp) imp.textContent = `Calendarr ${APP_VERSION}`;
+  const side = document.getElementById('sidebar-copyright');
+  if (side) side.innerHTML = `© 2026 Scarriffleservices · ${APP_VERSION}`;
 });
 
 // Fetch avatar image as blob URL (with auth header)