Key types, confirmed rotation and snapshot guides

The updated documentation separates Credits API keys from Subscription API keys, explains how credits and usage limits interact, and adds practical guides for each group of API requests.

The dev release adds key_type to /v1/usage/info and a confirmation flow for rotating either existing key through the API bot. After a successful rotation, the previous key can remain accepted for up to 60 seconds. See authentication and rotation.

The API reference now includes all 33 operations in the reviewed dev contract. Its downloadable OpenAPI file is the same artifact used to generate the reference.

The new snapshots and diffs guide covers saved catalog selections, comparisons against the original baseline, pagination, deletion, retention and plan limits. Snapshot access is prepared for Credits Advanced and Team, with individual settings for Subscription keys. Public snapshot activation remains pending pricing approval and release verification.

For client libraries, follow the current SDK guidance: use a standard HTTP client or generate a client from the downloaded contract.