Summary of the changes (Less than 80 chars)

• Added support for Model Context Protocol.

Related to #8197

📃 To-do:

• Fix the required property for output schemas (⛔ waiting for new "IsDirectConditional" or similar API).
• Endpoint routing "MapGraphQLMcp".
• OperationCompiler object pool (?). (⛔ waiting to discuss)
• Add additionalProperties: true/false to input schema. (⛔ waiting to discuss access to InputParserOptions)
• Output schema.
• Send tools/list_changed notification.
• Add tests for string patterns.
• Auth
• $list: [String!]! # = ["default"] FIXME: The validation might be broken.
• FIXME: It should not be necessary to provide this variable.
• Documentation
• TODO: Treating all unknown scalar types as strings is a temporary solution.
• Add support for decimal and long types serialized as strings.

❓ Questions

• Is GetGraphQLType correct? Is there another way to do this?

📝 Notes

• I've made the format of the TimeSpanType public so that this information can be accessed externally.
• File input is not supported. This requires additional planning.