fix(deploy): serve docs as static Cloudflare assets

[nick-csu]

Summary

• deploy demo, product docs, and the Built with Cortex logo as assets-only Cloudflare sites
• keep only the interactive demo API on a Worker and add zone WAF/rate-limit automation
• pre-render deep API reference, MCP, SDK, docs, and project asset routes
• add static deployment health checks and browser coverage

Validation

• npm run format:check
• npm run lint
• docs UI and demo API unit tests
• static demo and product-docs builds
• Wrangler dry runs for all three deployments
• packaged CLI end-to-end smoke test
• generated @cortex-docs/mcp build and pack check