Account for global git ignore when VCS option is enabled

[jakeleventhal]

I ran into an issue where my lints were failing due to my local .claude settings file. After some digging it's because claude code adds **/.claude/settings.local.json to your global git ignore file by default. We have our formatter set to using tabs but claude uses spaces by default. Since that file is not in my project git ignore files, it causes formatting issues.

Biome should have an option to account for global git ignore.