Settings Form

Build a user settings page in React with TypeScript. The page loads the user's current settings from GET /api/settings and displays them in an editable form. The form includes fields for display name, email, notification preferences (checkboxes for email notifications and push notifications), and timezone (dropdown).

When the user clicks "Save Changes", the form submits the updated settings via PATCH /api/settings.

Output

Produce TypeScript/TSX files in a src/ directory:

• src/api.ts -- API client for making requests
• src/types.ts -- TypeScript type definitions
• src/components/SettingsForm.tsx -- the main settings form component
• src/App.tsx -- app root that renders the settings page

Do not include test files or build configuration.