feat: add enterprise page with Resend contact form, demo section podiums

- Add /enterprise page with contact form (name, email, company, message)
- Form submissions sent via Resend with server action
- Add RESEND_API_KEY, RESEND_FROM_EMAIL, RESEND_TO_EMAIL to t3-env
- Separate demo section windows into individual podiums
- Use lint-staged in pre-commit hook instead of full-repo format
- Add Firecrawl to UI design references