feat: add news section with admin editor and public display

- NewsItem type with title, text, date, optional image and link
- Admin page at /admin/news with image upload and auto-date
- Public section between Pricing and FAQ, hidden when empty
- Nav link auto-hides when no news items exist

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

src/types/content.ts

@@ -88,6 +88,14 @@ export interface MasterClassItem {
   instagramUrl?: string;
 }
 
+export interface NewsItem {
+  title: string;
+  text: string;
+  date: string;
+  image?: string;
+  link?: string;
+}
+
 export interface ContactInfo {
   title: string;
   addresses: string[];
@@ -141,5 +149,9 @@ export interface SiteContent {
     title: string;
     locations: ScheduleLocation[];
   };
+  news: {
+    title: string;
+    items: NewsItem[];
+  };
   contact: ContactInfo;
 }