Enhance UI and Accessibility (WCAG)

- Add 'Skip to main content' links to App and Guest layouts.
- Add aria-current to navigation links for active page indication.
- Add aria-label to mobile menu button.
- Include pending UI updates for Dashboard and Welcome pages with improved structure.

resources/views/components/nav-link.blade.php

@@ -6,6 +6,6 @@ $classes = ($active ?? false)
             : 'inline-flex items-center px-1 pt-1 border-b-2 border-transparent text-sm font-medium leading-5 text-gray-500 hover:text-gray-700 hover:border-gray-300 focus:outline-none focus:text-gray-700 focus:border-gray-300 transition duration-150 ease-in-out';
 @endphp
 
-<a {{ $attributes->merge(['class' => $classes]) }}>
+<a {{ $attributes->merge(['class' => $classes]) }} @if($active) aria-current="page" @endif>
     {{ $slot }}
 </a>