fix:close transport on connection failure

[sid293]

Fixes a resource leak on connection failure and resolves TypeScript error in packages/client/test/client/auth.test.ts.

Motivation and Context

client.ts: Moved super.connect() inside the try block so the catch block can properly close the transport if initialization fails.

auth.test.ts: Added as unknown as RequestInit to resolve a type mismatch on the optional cache property.

How Has This Been Tested?

Added a new integration test to verify that the transport is closed even when startup fails.
All tests were verified passing using the workspace-wide command: pnpm test:all

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

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Latest commit: 28792b5

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commit: 28792b5

[felixweinberger]

Hi @sid293 thanks for this - did you come across this in something you were working on or is this purely speculative based on reading the source?

Some context for how you ran into this issue would be great.

[felixweinberger]

If we need this type assertion to make this work, that's a sign the solution isn't quite there yet.