fix: update shop layout and CSS selectors for shop-root

- Fix asset paths in shop layout (css/app.css, js/app.js)
- Add Google Fonts preconnect and stylesheet link
- Update theme-layer2-attributes.css to target both .preview-frame
  and .shop-root so theme styles apply to real shop pages
- Properly duplicate attribute selectors (e.g., [data-mood="warm"])
  for both .preview-frame and .shop-root

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

lib/simpleshop_theme_web/components/layouts/shop.html.heex

@@ -5,8 +5,14 @@
     <meta name="viewport" content="width=device-width, initial-scale=1" />
     <meta name="csrf-token" content={get_csrf_token()} />
     <.live_title><%= assigns[:page_title] || @theme_settings.site_name %></.live_title>
-    <link phx-track-static rel="stylesheet" href={~p"/assets/app.css"} />
-    <script defer phx-track-static type="text/javascript" src={~p"/assets/app.js"}>
+    <link phx-track-static rel="stylesheet" href={~p"/assets/css/app.css"} />
+    <link rel="preconnect" href="https://fonts.googleapis.com" />
+    <link rel="preconnect" href="https://fonts.gstatic.com" crossorigin />
+    <link
+      href="https://fonts.googleapis.com/css2?family=Cormorant+Garamond:wght@400;500;600&family=DM+Sans:opsz,wght@9..40,400..700&family=Fraunces:opsz,wght@9..144,400..700&family=Inter:wght@300..700&family=Manrope:wght@400..700&family=Outfit:wght@300..600&family=Playfair+Display:wght@400;500;700&family=Raleway:wght@300;400;500&family=Source+Serif+4:wght@400;600&family=Space+Grotesk:wght@400..600&family=Work+Sans:wght@300..600&display=swap"
+      rel="stylesheet"
+    />
+    <script defer phx-track-static type="text/javascript" src={~p"/assets/js/app.js"}>
     </script>
     <!-- Generated theme CSS (only active values, not all variants) -->
     <style id="theme-css"><%= Phoenix.HTML.raw(@generated_css) %></style>