Delete CLAUDE.md (GH-157799)

Claude Code 2.1.277 now supports AGENTS.md:

> Added AGENTS.md support: in a project with no CLAUDE.md, Claude Code reads AGENTS.md instead; change it under “Project instructions” in `/config` (not yet on Bedrock, Vertex or Foundry) 


https://code.claude.com/docs/en/changelog#2-1-277

Author: hugovk