Add a Cloudflare Python Workers counter deployment example #987

Is your feature request related to a problem? Please describe.

#390 requests deployment examples for additional cloud providers, with a separate issue for each target. Add a Cloudflare Python Workers example following the scope of the merged Vercel deployment example (#605).

Describe the solution you'd like

Add examples/deployment/cloudflare/ with the same Burr counter application, a POST /api/counter HTTP entrypoint, the required Workers configuration, and instructions for local testing and cloud deployment. A request containing {"number": 5} should return the counter's serialized Burr State.

Describe alternatives you've considered

Use the existing Vercel or AWS Lambda example. A Cloudflare version would demonstrate how to adapt the same application to Python Workers.

Additional context

Implementation: #988. Each request starts a new counter. The PR includes local and cloud deployment instructions and reports the results of HTTP smoke checks against both environments.

Tooling disclosure: the contribution and submission text were prepared with OpenAI Codex assistance.