Switch commits Fusion produces (both executor step commits and merger squash
commits) from setting `--author="Fusion <noreply@runfusion.ai>"` to appending
`-m "Co-authored-by: Fusion <noreply@runfusion.ai>"`. The user's configured
git identity now stays as the primary author/committer, and Fusion is recorded
as a co-author (recognized by GitHub for shared attribution). The
`commitAuthorEnabled` toggle and `commitAuthorName`/`commitAuthorEmail`
settings keep their existing keys; the dashboard settings UI relabels them
from "Author" to "Co-author" to match.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
e291d86444