feat: Add titles field

[bzsurbhi]

Add title field to Resource, Tool, Prompt, ClientInfo, and ServerInfo definitions in the spec.

Motivation and Context

By introducing title as a dedicated property, we ensure clarity and consistency in how data is surfaced to end users, improving both developer experience and user-facing usability as the protocol evolves.

How Has This Been Tested?

Added tests

Breaking Changes

None

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