Claude Code not respecting includeCoAuthoredBy: false setting in commits

### Description
Claude Code is attempting to manually add "Generated with Claude Code" and "Co-Authored-By: Claude <noreply@anthropic.com>" to git commit messages even when includeCoAuthoredBy is set to
false in settings.json.

### Expected Behavior
When includeCoAuthoredBy: false is set in ~/.claude/settings.json, Claude Code should:

• Never add any Claude-related signatures to commits
• Respect user settings automatically without requiring manual intervention

### Actual Behavior
Claude Code attempts to manually include the signature in commit messages via heredoc, ignoring the user's settings configuration.

### Reproduction Steps

1. Set "includeCoAuthoredBy": false in ~/.claude/settings.json
2. Ask Claude Code to commit changes
3. Observe that it attempts to add signatures despite the setting

### Configuration
```json
{
"includeCoAuthoredBy": false,
// ... other settings
}

Impact

This defeats the purpose of having settings if they can be overridden by Claude Code's behavior. Settings should be enforced constraints, not optional suggestions.