feat: add news section with admin editor and public article view

- NewsSection with animated grid background, category filters, featured cards
- AdminNews list page with toggle publish/featured, pagination
- AdminNewsCreate with TipTap rich text editor, URL validation
- NewsArticle detail page with DOMPurify sanitization, Telegram back button
- Toggle component with WCAG 44px touch targets, role=switch
- Prose styles for highlight marks and responsive iframes
- i18n translations (en, ru, zh, fa)

src/styles/globals.css

@@ -981,6 +981,14 @@ img.twemoji {
     @apply my-4 max-w-full rounded-xl;
   }
 
+  .prose mark {
+    @apply rounded bg-warning-500/30 px-1 text-dark-100;
+  }
+
+  .prose iframe {
+    @apply my-4 block aspect-video w-full max-w-2xl rounded-xl;
+  }
+
   /* Light theme prose styles */
   .light .prose {
     @apply text-champagne-800;
@@ -1054,6 +1062,14 @@ img.twemoji {
     @apply border-champagne-300 text-champagne-700;
   }
 
+  .light .prose mark {
+    @apply bg-warning-400/30 text-champagne-900;
+  }
+
+  .light .prose iframe {
+    @apply border border-champagne-300;
+  }
+
   /* Support for plain text with line breaks */
   .prose-plain {
     @apply whitespace-pre-line;
@@ -1522,6 +1538,19 @@ input[type='checkbox']:hover:not(:checked) {
   }
 }
 
+/* News section shimmer */
+@keyframes newsShimmer {
+  0%,
+  100% {
+    opacity: 0.3;
+    transform: scaleX(0.5);
+  }
+  50% {
+    opacity: 1;
+    transform: scaleX(1);
+  }
+}
+
 /* User preference: reduce motion */
 .reduce-motion,
 .reduce-motion * {