Deploy: Add Cloudflare Worker, D1 database integration, and updated README

- Add complete Cloudflare Worker implementation with waitlist API endpoints
- Integrate Cloudflare D1 SQLite database for production waitlist storage
- Add wrangler configuration for Worker deployment and D1 binding
- Rewrite README with comprehensive deployment and architecture documentation
- Update environment configuration and build setup
- Add waitlist utility functions and API client
- Update project dependencies and Vite configuration
- Deploy live to https://react-example.white-glade-ab2c.workers.dev

.gitignore

@@ -6,3 +6,8 @@ coverage/
 *.log
 .env*
 !.env.example
+
+# wrangler files
+.wrangler
+.dev.vars*
+!.dev.vars.example