API guides

The full endpoint reference is generated from the OpenAPI 3.1 document at /reference/. These guides cover the conventions the reference assumes:

• Errors: RFC 9457 problem documents and the machine-readable error taxonomy.
• Events: the CloudEvents catalog delivered by webhooks and the events feed.
• Webhooks: signed deliveries, verification, retries.
• Idempotency: Idempotency-Key semantics on every mutation.
• Rate limits: headers, limits, and back-off.