Added Idempotency Support for POST and PATCH Requests

This release introduces idempotency guarantees for selected non-idempotent methods (POST and PATCH).

Partners can now safely retry requests using the Idempotency-Key header without risk of duplicate processing. If a request with the same Idempotency-Key has already been processed, the API skips execution and returns the cached response with the header Idempotent-Replayed: true.

Change summary:

• Header (Request): Idempotency-Key (UUID v7 or ULID format recommended)
• Header (Response): Idempotent-Replayed (true for cached response, false for original)
• Retention: Keys stored for 24 hours

Refer to the "API Reference" for endpoints supporting this feature.