[FEATURE REQUEST] "🤖 Generated with Claude Code” should be opt-in

Question

When Claude Code commits something, it always adds:
```
🤖 Generated with Claude Code

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

- This is not appropriate in many contexts
- Uses precious tokens for Anthropic vanity

Having to counter this on ~/CLAUDE.md would be inconsistent, and it's a waste of tokens when this shouldn’t be in the base system prompt at all.

We should have more transparency and control over the base system prompt, at least the parts that are not critical such as th