feat ui foundation layer for page container sections and grid

src/app/pages/home/home.component.html

@@ -1,7 +1,11 @@
 @if (loading()) {
-  <section class="home-loading">Loading homepage...</section>
+  <section class="home-loading section">
+    <div class="page-container">Loading homepage...</div>
+  </section>
 } @else if (pageModel()) {
   <app-dynamic-page-layout [model]="pageModel()" />
 } @else {
-  <section class="home-empty">No page configuration found.</section>
+  <section class="home-empty section">
+    <div class="page-container">No page configuration found.</div>
+  </section>
 }

src/app/pages/public/platform-home.component.ts

@@ -10,11 +10,15 @@ import { WebsiteRuntimeFacade } from '../../facades/website/website-runtime.faca
   imports: [DynamicPageLayoutComponent],
   template: `
     @if (loading()) {
-      <section class="platform-loading">Loading platform page...</section>
+      <section class="platform-loading section">
+        <div class="page-container">Loading platform page...</div>
+      </section>
     } @else if (model()) {
       <app-dynamic-page-layout [model]="model()" />
     } @else {
-      <section class="platform-empty">No page configuration found.</section>
+      <section class="platform-empty section">
+        <div class="page-container">No page configuration found.</div>
+      </section>
     }
   `,
   styles: [