Implement relative paths for frontend API and WebSocket connections

- Created `.env.production` file to define relative paths for production deployment.
- Updated frontend API and WebSocket client to use environment variables for dynamic URL handling.
- Enhanced deployment scripts (`deploy-ubuntu.sh`, `start.sh`, `start.bat`) to generate `.env.production` automatically.
- Added `PRODUCTION_URLS.md` for documentation on production URL configuration and troubleshooting.

frontend/src/api/client.ts

@@ -1,7 +1,8 @@
 import axios from 'axios';
 import type { Repository, RepositoryCreate, Review, ReviewStats } from '../types';
 
-const API_BASE_URL = import.meta.env.VITE_API_URL || 'http://localhost:8000/api';
+// Используем относительный путь для production или env для development
+const API_BASE_URL = import.meta.env.VITE_API_URL || '/api';
 
 const api = axios.create({
   baseURL: API_BASE_URL,