Implements a rack-compatible Streamable HTTP transport with SSE support. As well as add notification support for the server with the following methods:

• notify_tools_list_changed() - Send a notification when the tools list changes
• notify_prompts_list_changed() - Send a notification when the prompts list changes
• notify_resources_list_changed() - Send a notification when the resources list changes

Closes #4

Motivation and Context

To fulfill the Streamable HTTP transport specification as described here.

How Has This Been Tested?

Local tests only (see examples/). Working on implementing it with my MCP server that's a WIP.

Breaking Changes

Should introduce no breaking changes as using the StreamableHTTP transport is optional

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

Local Tests

Started with run options --seed 59936

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