Module problem 

A minimal, product-neutral structured-error response body.

Not a full RFC 7807 “problem+json” implementation — just the small reusable subset every JSON API surface in this workspace already agrees on: an error value and an optional human-readable message. Product- specific error shapes (with retry hints, remediation text, scoped codes, etc.) stay in the owning product crate and may From-convert into this type at the response boundary.

error is a short machine-readable code (e.g. "validation_error") for call sites that classify their own failures. For framework-generated rejections with no natural short code — see json_rejection_response in response.rs — it is the framework’s raw rejection text instead; there is no stable code to assign a body-parsing failure that didn’t originate from this crate’s own validation logic.

Structs

ErrorBody

Generic JSON error body: {"error": "...", "message": "..."}.