complete admin CSS refactor: delete utilities.css, add layout primitives

- Delete utilities.css (701 lines / 24 KB of Tailwind utility clones)
- Add layout.css with admin-stack, admin-row, admin-cluster, admin-grid
  primitives and gap variants (sm, md, lg, xl)
- Add transitions.css import and layout.css import to admin.css entry point
- Replace all Tailwind utility classes across 26 admin templates with
  semantic admin-*/theme-*/page-specific CSS classes
- Replace all non-dynamic inline styles with semantic classes
- Add ~100 new semantic classes to components.css (analytics, dashboard,
  order detail, settings, theme editor, generic utilities)
- Fix stray text-error → admin-text-error in media.ex
- Add missing .truncate definition to admin CSS
- Only remaining inline styles are dynamic data values (progress bars,
  chart dimensions) and one JS.toggle target

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

lib/berrypod_web/live/admin/pages/editor.ex

@@ -521,10 +521,7 @@ defmodule BerrypodWeb.Admin.Pages.Editor do
   def render(assigns) do
     ~H"""
     <div id="page-editor" phx-hook="EditorKeyboard" data-dirty={to_string(@dirty)}>
-      <.link
-        navigate={~p"/admin/pages"}
-        class="text-sm font-normal text-base-content/60 hover:underline"
-      >
+      <.link navigate={~p"/admin/pages"} class="admin-back-link">
         &larr; Pages
       </.link>
       <.header>
@@ -552,7 +549,7 @@ defmodule BerrypodWeb.Admin.Pages.Editor do
           </button>
           <button
             phx-click="undo"
-            class={["admin-btn admin-btn-sm admin-btn-ghost", @history == [] && "opacity-30"]}
+            class="admin-btn admin-btn-sm admin-btn-ghost"
             disabled={@history == []}
             aria-label="Undo"
           >
@@ -560,7 +557,7 @@ defmodule BerrypodWeb.Admin.Pages.Editor do
           </button>
           <button
             phx-click="redo"
-            class={["admin-btn admin-btn-sm admin-btn-ghost", @future == [] && "opacity-30"]}
+            class="admin-btn admin-btn-sm admin-btn-ghost"
             disabled={@future == []}
             aria-label="Redo"
           >
@@ -584,7 +581,7 @@ defmodule BerrypodWeb.Admin.Pages.Editor do
           </button>
           <button
             phx-click="save"
-            class={["admin-btn admin-btn-sm admin-btn-primary", !@dirty && "opacity-50"]}
+            class="admin-btn admin-btn-sm admin-btn-primary"
             disabled={!@dirty}
           >
             Save
@@ -598,7 +595,7 @@ defmodule BerrypodWeb.Admin.Pages.Editor do
       </div>
 
       <%!-- Status badges --%>
-      <div class="mt-4 flex gap-2 flex-wrap">
+      <div class="admin-editor-badges">
         <p :if={@dirty} class="admin-badge admin-badge-warning">
           Unsaved changes
         </p>