feat: add smooth scroll-to-top button with Alpine transition

default.hbs

@@ -4,6 +4,7 @@
         theme: localStorage.getItem('theme') || (window.matchMedia('(prefers-color-scheme: light)').matches ? 'light' : 'dark'),
         mobileMenuOpen: false,
         currentPath: window.location.pathname,
+        showScrollTop: false,
         init() {
             $watch('theme', val => {
                 localStorage.setItem('theme', val);
@@ -12,6 +13,11 @@
             document.documentElement.setAttribute('data-theme', this.theme);
             document.documentElement.classList.remove('hidden');
 
+            // Handle scroll for scroll-to-top button
+            window.addEventListener('scroll', () => {
+                this.showScrollTop = window.scrollY > 400;
+            });
+
             // Update currentPath on navigation to keep menu highlights in sync
             document.addEventListener('htmx:afterSettle', () => {
                 this.currentPath = window.location.pathname;
@@ -49,6 +55,7 @@
     --}}
     {{> mobile-menu}}
     {{> header}}
+    {{> scroll-top}}
 
     <main id="main-content" class="flex-grow">
         {{{body}}}