Server feature list changed and resource updated notifications

[tiginamaria]

Motivation and Context

Implemented thread-safe notification service following eventual consistency principle.
Fixes #249
Contracts:

• If the client connection and feature update happened in the same thread, the timestamps of the events will be consequent

server.connect(client)
server.add(feature)
// client will receive the notification

server.add(feature)
server.connect(client)
// client will NOT receive the notification

• If the client connection and feature update happened in the different threads, both options can be possible

The flow of the notification is explained in the diagram:

Documentation references:
https://modelcontextprotocol.io/specification/2025-06-18/server/prompts#list-changed-notification
https://modelcontextprotocol.io/specification/2025-06-18/server/tools#list-changed-notification
https://modelcontextprotocol.io/specification/2025-06-18/server/resources#list-changed-notification
https://modelcontextprotocol.io/specification/2025-06-18/server/resources#subscriptions

Questions:

• I haven't found the subscription confirmed response message content docs, how it should look like?

How Has This Been Tested?

Multiple tests with various notification scenarios were added

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

[kpavlov]

Thank you, @tiginamaria very good PR

I have few comments about logging, but it can be addressed in a separate PR