bug: Client.CallTool does not handle header.

[mrh997]

Description

Client.CallTool does not handle header.

Code Sample

// Minimum code snippet to reproduce the issue
// Remove if not applicable

Logs or Error Messages

If applicable, include any error messages, stack traces, or logs. Remove if not applicable.

Environment

• Go version (see go.mod): [e.g. 1.23]
• mcp-go version (see go.mod): [e.g. 0.27.0]
• Any other relevant environment details (OS, architecture, etc.)

Additional Context

Add any other context about the problem here.

Possible Solution

If you have a suggestion for fixing the issue, please describe it here.