Add missing dependency eventsource-parser

[jshao-brex]

The Streamable HTTP client uses eventsource-parser https://github.com/modelcontextprotocol/typescript-sdk/blob/main/src/client/streamableHttp.ts#L4 but didn't explicitly add the dependency to packages.json.

This caused a runtime module not found error with apps built with rules_js Bazel, which requires stricter dependency declaration.

Motivation and Context

How Has This Been Tested?

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

Additional context

[ihrpr]

thank you for working on this!

I can see CI is failing, please can you check what's happening there?