Continue trying other discovery endpoints when CORS errors occur instead of failing immediately.

Motivation and Context

Authorization servers don't always allow CORS requests for all potential metadata discovery endpoints, especially for non-public information. The client tries multiple well-known endpoints, and CORS failures are common and expected. Previously, a CORS error on any endpoint would cause the entire discovery process to fail immediately, even though other endpoints might work.

How Has This Been Tested?

• Unit test added
• Tested implementation manually in MCP Inspector

Breaking Changes

None.

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

Changed discoverAuthorizationServerMetadata to use continue instead of throwing when CORS errors occur, allowing the function to try all available discovery URLs before giving up.