chore: update dependencies and add Cloudflare support

- Updated dependencies in package.json for Astro, React, and testing libraries.
- Added .assetsignore to exclude specific files from asset uploads.
- Refactored AccountSummary, MainContent, and Sidebar components for clarity and maintainability.
- Enhanced tsconfig.json to support React JSX syntax.
- Created wrangler.jsonc for Cloudflare Workers configuration.

src/components/AccountSummary.astro

@@ -1,5 +1,5 @@
 ---
-import { formatCurrency } from '../utils'; // We'll create this util
+import { formatCurrency } from '../utils';
 import type { Account } from '../types';
 
 interface Props {
@@ -10,5 +10,4 @@ const { account } = Astro.props;
 <div class="account-summary">
      <h4>Account Summary</h4>
      <p>Balance: <span id="account-balance">{formatCurrency(account.balance)}</span></p>
-     <!-- Add more summary info if needed -->
 </div>