* Add comprehensive mobile support with responsive navigation

- Add hamburger drawer navigation for mobile (< 768px)
  - Create useIsMobile hook for responsive breakpoint detection
  - Create useLongPress hook for touch gesture context menus
  - Update Button component with 44px min-height for WCAG touch compliance
  - Update Toggle component with larger mobile size (44x28px)
  - Add responsive padding (p-4 md:p-8) to all pages
  - Update ArchivesPage with mobile menu button and horizontal scroll filters
  - Update SettingsPage with stacked column layout on mobile
  - Increase drag handle sizes for touch-friendly reordering
  - Add CSS utilities for touch-manipulation and safe-area insets

frontend/src/index.css

@@ -143,3 +143,41 @@ body {
     #333 4px
   );
 }
+
+/* Touch manipulation to prevent zoom on double-tap */
+.touch-manipulation {
+  touch-action: manipulation;
+}
+
+/* Safe area insets for notched devices */
+.safe-area-bottom {
+  padding-bottom: env(safe-area-inset-bottom, 0);
+}
+
+.safe-area-top {
+  padding-top: env(safe-area-inset-top, 0);
+}
+
+/* Hide scrollbar but keep functionality */
+.scrollbar-hide {
+  -ms-overflow-style: none;
+  scrollbar-width: none;
+}
+
+.scrollbar-hide::-webkit-scrollbar {
+  display: none;
+}
+
+/* Mobile drawer animation */
+@keyframes slide-in-left {
+  from {
+    transform: translateX(-100%);
+  }
+  to {
+    transform: translateX(0);
+  }
+}
+
+.animate-slide-in-left {
+  animation: slide-in-left 0.3s ease-out;
+}