chore(docs): Revise Maintainers list in README.md

[markscott-ms]

Description

Following on from #2024, discussed at #2039 and #2055 , I'm raising this change that:

• Changes the term "Lead Maintainer" in README.md to be "Maintainer", to reduce confusion with respect to Governance.md
• Adds myself to projects where I believe I have given significant contribution over the past 7 months, specifically:
  • Contributions to getting CALM Schema through the RC period to 1.0, and then proposals beyond (currently slated for 1.2)
  • Ongoing bugfixes to the CALM CLI and its constituent libraries, with additional impact to VSCode Extension.

Comments and/or discussion are welcomed in #2064 on my proposal, plus any other changes we wish to make to recognise contribution of Maintainers, or absence thereof. I will keep this PR in Draft status until after that office hours meeting.

Type of Change

• 🐛 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 not work as expected)
• 📚 Documentation update
• 🎨 Code style/formatting changes
• ♻️ Refactoring (no functional changes)
• ⚡ Performance improvements
• ✅ Test additions or updates
• 🔧 Chore (maintenance, dependencies, CI, etc.)

Affected Components

• CLI (cli/)
• Shared (shared/)
• CALM Widgets (calm-widgets/)
• CALM Hub (calm-hub/)
• CALM Hub UI (calm-hub-ui/)
• Documentation (docs/)
• VS Code Extension (calm-plugins/vscode/)
• Dependencies
• CI/CD

Commit Message Format ✅

Testing

• I have tested my changes locally
• I have added/updated unit tests
• All existing tests pass

Checklist

• My commits follow the conventional commit format
• I have updated documentation if necessary
• I have added tests for my changes (if applicable)
• My changes follow the project's coding standards