OAuth Client Provider for Streamable HTTP Client

[aravind-segu]

Motivation and Context

Issue: #652

Introduces a OAuthProvider for Streamable HTTP Client, which allows to authenticate to the HTTP Client through the OAuth. This follows a similar architecture to the typescript auth provider: https://github.com/modelcontextprotocol/typescript-sdk/blob/621ccea997bf318ee99c7f64ce19609e838615fa/src/client/auth.ts#L13

How Has This Been Tested?

Unit tests, and tested with Databricks OAuth App

Breaking Changes

streamablehttp_client() now returns a finish_auth method which needs to be called after the OAuth redirect. If the users were unpacking this as a tuple, they now can get an extra return value in the tuple. This is not a big breaking change, but might error out for some users depending on their implementation.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update

Checklist

• I have read the MCP Documentation
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling
• I have added or updated documentation as needed

Additional context

[ihrpr]

Thank you @aravind-segu!! Sorry I just saw this one, as discussed in previous PRs, we should have support for Auth in Client now.