Document the OpenAPI HTTP interoperability boundary #121

Parent

Spec: Complete the review-driven Effect API Query 0.1.0 programme

What to build

OpenAPI guidance describes the declared HTTP contract and external-client boundary, backed by useful ordinary protocol evidence.

Acceptance criteria

• Retain method/path and detailed request layout, declared failures, multipart, SSE, and buffered metadata contracts in guidance and ordinary protocol evidence.
• Name the external client/version scope and distinguish encoded DTO consumption from native RPC wire compatibility and ready-client interchangeability.
• Keep Effect factories native and place schema interoperability at the external boundary.
• Provide useful recipes, ordinary protocol evidence, and documented unsupported shapes without a new adapter/server stack or application.