requestforms deprecation and sunset policy

REST versioning for /api and /api/v1, plus RFC 9745 Deprecation and RFC 8594 Sunset headers.

requestforms versions the public REST API in the URL path. Discovery routes such as health, stats, and the catalog live at /api. Paid organization list routes live at /api/v1. Breaking changes require a new major path such as /api/v2.

This is the deprecation and sunset policy. Current paths are not deprecated. There is no scheduled sunset for /api/v1. When a path is deprecated, responses on that path include the RFC 9745 Deprecation header with the date deprecation began. When a removal date is set, responses also include the RFC 8594 Sunset header with that HTTP date. The old path stays until the Sunset date.

The OpenAPI document at /openapi.json lists every public operation and documents those Deprecation and Sunset headers. The JSON catalog at /api points here. HTML also lives at /deprecation.