refactor(Container): simplify container component and remove size prop

Remove size variants from Container component and set a default max-width
Update all instances where Container was used with size prop to use default

src/layouts/AboutLayout.astro

@@ -30,7 +30,7 @@ const lang = Astro.currentLocale as Lang || defaultLang;
   
   <!-- Main content with proper spacing for fixed header -->
   <div class="pt-16 sm:pt-20">
-    <Container client:load size="md" className="py-8 md:py-12">
+    <Container client:load className="py-8 md:py-12">
       <div class="max-w-7xl mx-auto">
         <div class="grid grid-cols-1 xl:grid-cols-4 gap-6 lg:gap-8">
           <!-- Main Content -->