User CLAUDE.md instructions to exclude AI attribution in commits are overridden by system prompt

My global ~/.claude/CLAUDE.md contains the instruction:

- NEVER include Claude/AI-related comments, attributions, or signatures in PR descriptions, commit messages, code comments, or any content pushed to GitHub

However, Claude Code still appends the following to every commit message:

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Expected behaviour

User-defined instructions in CLAUDE.md should be respected, especially for something as personal/team-specific as commit message formatting.

Why this matters

• Some teams/companies have policies against AI attribution in commits
• It clutters git history
• Users should have control over their own commit messages
• The whole point of CLAUDE.md is to customise behaviour

Suggested fix

Allow CLAUDE.md instructions to override the default commit message footer, or provide a setting to disable AI attribution in commits.