feat: add items for array type in McpSchema.JsonSchema

[liupx]

Motivation and Context

To support array types, the items property needs to be added to McpSchema.JsonSchema.
For reference:
Array Type In JsonSchema

How Has This Been Tested?

Breaking Changes

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