remove Gemfile.lock

[topherbullock]

Motivation and Context

ci on #10 is failing due to Darwin deps in the lockfile;

Could not find gems matching 'sorbet-static (= 0.5.11495)' valid for all
resolution platforms (arm64-darwin-23, ruby) in rubygems repository
https://rubygems.org/, cached gems or installed locally.
The source contains the following gems matching 'sorbet-static (= 0.5.11495)':
  * sorbet-static-0.5.11495-aarch64-linux
  * sorbet-static-0.5.11495-java
  * sorbet-static-0.5.11495-universal-darwin
  * sorbet-static-0.5.11495-x86_64-linux
Error: The process '/home/runner/.rubies/ruby-head/bin/bundle' failed with exit code 7

fix ci by removing the gemfile and adding bundle install to ci steps

How Has This Been Tested?

I created a branch based on the changes in #10 and ran CI and it passed

Breaking Changes

N/A

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

https://github.com/modelcontextprotocol/ruby-sdk/actions/runs/15140806419/job/42564088428