Jsonrpc refactor

[Cloudkkk]

Motivation and Context

This change addresses the issue of repetitive code in JSON-RPC error handling by introducing a centralized sendJSONRPCError function and standardized error constants. This refactoring follows the DRY (Don't Repeat Yourself) principle

How Has This Been Tested?

Existing unit and integration tests verify that error handling functionality remains consistent
Manual testing of various error scenarios to ensure correct HTTP status codes and JSON-RPC error formatting
Verified backward compatibility with existing client code

Breaking Changes

No breaking changes. This is an internal refactoring that doesn't affect public APIs.

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