Attribution settings not honored - Co-Authored-By and PR footer added despite empty attribution config

Bug Description

Claude Code does not honor the attribution settings in ~/.claude/settings.json. Despite having attribution disabled, Claude still adds:

• Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com> to commits
• 🤖 Generated with [Claude Code](https://claude.ai/code) footer to PRs

Settings Configuration

~/.claude/settings.json:

{
  "attribution": {
    "commit": "",
    "pr": ""
  }
}

Expected Behavior

With empty strings for commit and pr attribution, no attribution lines should be added to commits or pull requests.

Actual Behavior

Claude follows the default system prompt instructions to add attribution, ignoring the user's settings configuration.

Steps to Reproduce

1. Configure ~/.claude/settings.json with empty attribution strings (as shown above)
2. Ask Claude to make a commit or create a PR
3. Observe that attribution is still added despite the setting

Additional Context

Claude acknowledged the settings exist and are correctly configured, but the settings don't appear to be injected into the model's context or don't override the default instructions.