Add header to MCP server to expand authentication capabilities

[termixai-it]

Motivation and Context

This change introduces header-based authentication for MCP, improving security and access control. By requiring authentication headers in requests, we ensure that only authorized users can interact with MCP services.

How Has This Been Tested?

• Added unit tests to verify authentication header validation.
• Tested authentication flow in a real application environment.
• Ensured that unauthorized requests are correctly rejected while maintaining backward compatibility.

Breaking Changes

No breaking changes; existing authentication mechanisms remain functional, and this addition does not affect previous implementations.

Types of changes

• New feature (non-breaking change which adds functionality)

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

This implementation enhances security while keeping the request structure simple and efficient. No changes were made to the core authentication logic beyond requiring the new header.