Add news feature with CRUD operations and real-time notifications

- Implemented news management functionality, allowing admins to create, read, update, and delete news posts.
- Introduced a new SignalR event for broadcasting news updates to all connected clients.
- Updated API documentation to include new endpoints for news management.
- Enhanced frontend with a dedicated news page and admin interface for managing news posts.
- Added necessary localization for news-related terms in both Russian and English.

frontend/package.json

@@ -34,7 +34,9 @@
     "react-dom": "^19.2.7",
     "react-hook-form": "^7.80.0",
     "react-i18next": "^17.0.8",
+    "react-markdown": "^10.1.0",
     "recharts": "^3.9.1",
+    "remark-gfm": "^4.0.1",
     "tailwind-merge": "^3.6.0",
     "zod": "^4.4.3",
     "zustand": "^5.0.14"