refactor SseClientTransport

[devcrocod]

• cancellation exception
• clean up code

How Has This Been Tested?

locally

Breaking Changes

no

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

[Copilot]

Pull Request Overview

This PR refactors the SSE client transport implementation—improving cancellation handling and cleaning up connection logic—and updates integration and unit tests to use dynamic ports and ensure resources are closed.

• Tests now capture and close the client, use port 0 with actualPort(), and wrap cleanup in try/finally.
• SseClientTransport was reorganized: message collection extracted, added handleEndpoint/handleMessage, and consolidated resource cleanup.

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
SseIntegrationTest.kt	Introduced client variable, catch/fail wrapper, and ensured client/server closures
SseTransportTest.kt	Switched to dynamic ports via actualPort(), added try/finally around server stop
SSEClientTransport.kt	Rewrote start, extracted collectMessages, handleEndpoint, handleMessage, and unified cleanup in closeResources

[e5l]

lgtm, please check if we need to handle more general exception type

[e5l]

lgtm