Description:
For the WXO use case, credentials should not be stored during MCP Gateway registration. We need a one-time authentication mode where credentials are used temporarily for authentication and tool listing, and also support credential passthrough for subsequent tool executions via the virtual server.

Proposed Change:

• Add a flag one_time_authentication: true in registration.

• When enabled, use credentials only for initial authentication and tool discovery—do not persist them.

• Allow pass-through headers in the virtual server so that credentials can be sent dynamically during tool execution instead of being stored in the DB.

Expected Outcome:
Enables secure, stateless integration with WXO—credentials are used only at runtime for listing or invoking tools, ensuring compliance with non-persistent authentication requirements.