OAuth Dynamic Client Registration Support

NetBrain's OAuth implementation currently requires each client integration to be manually registered and configured by an administrator before it can authenticate, with no support for clients to register themselves programmatically. This limits organizations that connect multiple dynamic or third-party MCP clients, as each new client requires manual setup effort before it can establish a connection. This enhancement would add support for OAuth Dynamic Client Registration, allowing compatible clients to register with NetBrain's authorization server automatically and receive credentials without administrator intervention for each individual client. Customers integrating a growing number of AI assistant or automation tools would benefit from reduced administrative overhead and faster, more consistent onboarding of new OAuth-based integrations.