Bump codejson-core to 0.2.0

[sachin-panayil]

Use codejson-core 0.2.0 and remove the draft workaround

Problem

codejson-core 0.1.1 couldn't produce an incomplete draft code.json, so this
action carried its own workaround to fill that gap. That was left as a
follow-up in #138.

Solution

Bump codejson-core to 0.2.0, which supports drafts natively, and use its CMS
profile directly. The local workaround and its tests are removed.

This PR is stacked on #156.

AI Usage

• Generated AI was used in this contribution
• Description:
  • Claude helped guide and double check the changes and update tests. All changes were reviewed by hand.
• Type of Assistance:
  • Code generation
  • Documentation
  • Debugging
  • Testing
  • Refactoring
  • Other:
• AI System Used:
  • ChatGPT
  • Claude
  • Gemini
  • GitHub Copilot
• Level of Modification:
  • As-is
  • Modified
  • Used as inspiration

Result

The action generates the same code.json as before with less code to maintain in this repository.

Test Plan

• npm test, npm run lint and npm run package
• Run against a test repository with an existing code.json and confirm the
  only change is date.metadataLastUpdated.

[natalialuzuriaga]

LGTM! The policy-based recursive merging feature is going to be a game changer with keeping code.json files up-to-date going forward