fix(frontend): add explicit React imports to resolve UMD global type errors

Author: ogazboiz

frontend/components/Dashboard.tsx

@@ -1,7 +1,9 @@
+import React from 'react';
 import { ActivityHistory } from './dashboard/ActivityHistory';
 import { fetchUserEvents } from '@/lib/dashboard';
 import { useWallet } from '@/context/wallet-context';
 import { BackendStreamEvent } from '@/lib/api-types';
+import { downloadCSV } from '@/utils/csvExport';
 
 interface StreamData extends Record<string, unknown> {
     id: string;

frontend/components/wallet/WalletModal.tsx

@@ -12,7 +12,7 @@
  * - Dismiss via Escape key or backdrop click.
  */
 
-import React, { useEffect, useCallback } from "react";
+import React, { useEffect, useCallback, useState } from "react";
 import { type WalletId } from "@/lib/wallet";
 import { useWallet } from "@/context/wallet-context";