[FEATURE] Use `Assisted-by` git commit trailer instead of `Co-authored-by`

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

Hi,

I've seen people contributing to my projects using Claude Code and these git commits include the Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com> trailer. (example).

Proposed Solution

I think it'd be more appropriate to use Assisted-by trailer as it's recommended by several big projects:

• Linux Kernel
• Fedora
• LLVM

Alternative Solutions

I know this could be configured, I'm asking for changing the default so it doesn't need to be configured.

Priority

Medium - Would be very helpful

Feature Category

API and model interactions

Use Case Example

1. Someone is creating commits using Claude Code
2. They include correct Assisted-by git trailer instead of Co-Authored-By.

Additional Context

More context and in depth discussion of this is at https://fabiorehm.com/blog/2026/03/02/our-coding-agent-commits-deserve-better-than-co-authored-by/