feat(playlist): enhance public playlist index with hero stats and loading optimizations

Add a redesigned hero section to the public playlist page displaying
community-generated totals for playlists and episodes, plus new string
translations (English, German, French). Eager-load user, limited episode
previews, and first gallery image to reduce N+1 queries. Cache aggregate
statistics for 10 minutes to improve performance on high-traffic pages.

resources/views/playlist/index.blade.php

@@ -1,11 +1,5 @@
 <x-app-layout>
-    <x-slot name="header">
-        <h2 class="font-semibold text-xl text-gray-800 dark:text-gray-200 leading-tight z-10">
-            {{ __('nav.public-playlists') }}
-        </h2>
-    </x-slot>
-
-    <div class="max-w-6xl mx-auto sm:px-6 lg:px-8">
+    <div class="mx-auto pt-6 sm:px-6 lg:px-8 max-w-[100%] xl:max-w-[95%] 2xl:max-w-[85%]">
         @include('partials.background')
         @livewire('playlists')
     </div>