OAuth: Additional Grant Types

[Radiergummi]

Description

Additional OAuth 2.0/2.1 grant types including Client Credentials and enhanced Refresh Token handling.

Implemented

• ✅ Client Credentials Grant
• ✅ Basic Refresh Token Grant

Remaining Work

• Refresh token rotation configuration
• Token exchange (RFC 8693)
• Assertion grants (JWT bearer)
• SAML assertion grant

Files

• Plan: plans/oauth-additional-grants.md

Getting Started

1. Review existing grant implementations
2. Add configurable refresh token rotation
3. Implement token exchange