Versioning

URI-versioned from day one.

The API is versioned in the path: /api/v1. Within a version, we add fields but do not break existing ones.

• Breaking changes ship under a new version prefix, with migration guidance communicated in advance.
• New optional response fields may be added within v1 — parse defensively (ignore unknown fields).
• The API reference is generated from the OpenAPI 3.1 spec, the single source of truth.