replace orphaned tailwind classes with project CSS

auth pages (login, registration, confirmation, recover) now use
setup-page/setup-header/admin-btn-block. theme toggle indicator
gets proper CSS. cleaned up dead h-full, size-3.5, ml-2 classes.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

lib/berrypod_web/components/shop_components/content.ex

@@ -928,12 +928,10 @@ defmodule BerrypodWeb.ShopComponents.Content do
   ## Attributes
 
   * `text` - Required. The title text.
-  * `class` - Optional. Additional CSS classes.
 
   ## Examples
 
       <.page_title text="Your basket" />
-      <.page_title text="Order History" class="mb-4" />
   """
   attr :text, :string, required: true