Added UI to provide additional _meta values

[ln-12]

This PR adds a UI section inside the tools tab which enabled the user to provide extra key-value pairs for the _meta object. Fixes #559.

UI:

Request:

Motivation and Context

Currently there is no way to provide additional _meta values in the UI.

How Has This Been Tested?

I provided values in the UI and checked that they are sent in the request. Also, I added a test.

Breaking Changes

No

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

[ln-12]

I also added another section to the main UI so that it is possible to add meta data for all calls (like initialize, tools/list, ...):