Civitai OAuth API
OAuth 2.0 authorization-code with PKCE for third-party apps that act on behalf of a Civitai user. Supports scoped tokens, refresh flow, and per-app Buzz spend caps so a delegated app cannot drain a user's credit balance. Used by `civitai-app-starters` and `civitai-client-javascript` SDKs for building partner integrations against the Site and Orchestration APIs.