feat: apply global fadeInUp animation to all page transitions

assets/js/main.js

@@ -20,6 +20,14 @@ document.addEventListener('DOMContentLoaded', () => {
     // Re-run animation and other setup when HTMX settles new content
     // Use document instead of document.body to persist across boosted navigation
     document.addEventListener('htmx:afterSettle', (event) => {
+        // Global page fade-in animation
+        const mainContent = document.getElementById('main-content');
+        if (mainContent) {
+            mainContent.classList.remove('animate-fadeInUp');
+            void mainContent.offsetWidth; // Force reflow to restart animation
+            mainContent.classList.add('animate-fadeInUp');
+        }
+
         // If the settled element is the posts-container or contains grid items
         const target = event.detail.target;
         if (target.id === 'posts-container' || target.querySelector('.post-grid-item')) {