feat: add environment configuration files and update API base URL handling for production

src/contexts/SocketContext.tsx

@@ -27,7 +27,12 @@ export function SocketProvider({ children }: SocketProviderProps) {
   const createSocket = useCallback(() => {
     if (!user) return null
 
-    const newSocket = io('http://localhost:8000', {
+    // Get socket URL - use relative URL in production with reverse proxy
+    const socketUrl = import.meta.env.PROD 
+      ? '' // Use relative URL in production (same origin as frontend)
+      : (import.meta.env.VITE_API_BASE_URL || 'http://localhost:8000')
+
+    const newSocket = io(socketUrl, {
       withCredentials: true,
       transports: ['polling', 'websocket'],
       timeout: 20000,