Refactor footer scripts into default layout and enhance service worker registration with sync capabilities

_layouts/default.html

@@ -9,10 +9,32 @@
     {{ content }}
   </main>
   {% include footer.html %}
+  <script src="{{ "/assets/js/materialize.min.js" | relative_url }}"></script>
+  <script>
+    document.addEventListener('DOMContentLoaded', function() {
+      var sidenavElems = document.querySelectorAll('.sidenav');
+      var sidenavInstances = M.Sidenav.init(sidenavElems, {});
+    });
+
+    document.querySelectorAll("button").forEach(button => {
+      const href = button.getAttribute("data-href");
+      if (!href) return;
+      button.addEventListener("click", () => {
+          window.location.href = button.getAttribute("data-href");
+      });
+    });
+  </script>
   <script>
     if ('serviceWorker' in navigator) {
       navigator.serviceWorker.register("{{ '/assets/js/service-worker.js' | relative_url }}")
-        .then(() => console.log("✅ Service Worker registriert"))
+        .then((reg) => {
+          console.log("✅ Service Worker registriert");
+          if ('SyncManager' in window) {
+            reg.sync.register('cache-all-pages')
+              .then(() => console.log("✅ Alle Seiten werden gecached"))
+              .catch(err => console.error("❌ Fehler beim Sync:", err));
+          }
+        })
         .catch(error => console.log("❌ Service Worker Fehler:", error));
     }
   </script>