docs: Fix README and CONTRIBUTING inconsistencies with implementation#56

atksh merged 3 commits intomainatksh/python_prtree:mainfrom

claude/verify-and-update-readme-011CUxJqAKK8x1okH4QngNmdatksh/python_prtree:claude/verify-and-update-readme-011CUxJqAKK8x1okH4QngNmdCopy head branch name to clipboard