Fix default branch — currently set to feature branch

[jeremyeder]

Problem

The default branch for this repo is set to feature/ambient-code-readme instead of main. This is likely unintentional and means branch protection rules targeting main would not apply to the actual default branch.

Action Required

1. Merge or rebase feature/ambient-code-readme into main if needed.
2. Set the default branch back to main via Settings > General > Default branch.
3. Enable branch protection on main (see separate issue).