residue v0.0.9

Faster size measurement on macOS, and a true line when residue has not counted any freed space yet.

• Faster on macOS. residue measures a worktree's size two to five times faster, with the same result to the byte. scan, explain, remove, automatic cleanup and the Mac app all measure this way. explain of a 98,000-file worktree takes about 1.0 s, down from 1.4 s (#72).
• What residue freed, said truthfully. Before residue has counted any freed space, service status, residue stats, the line after a removal and the Mac app say so. They said residue had never freed any space (#70).

Details

• On macOS, residue measures a worktree's size two to five times faster, with the same result to the byte. It reads each folder with one getattrlistbulk call, as du does, in place of one stat call per file. Folders, symbolic links and other entries that are not regular files still get stat, and a folder the call refuses is read as before. explain of a 98,000-file worktree takes about 1.0 s, down from 1.4 s; git status is most of what is left (#72).
• When nothing freed is counted yet, service status, residue stats, the line after a removal and the Mac app say so, and say that residue counts what it frees from version 0.0.8 on. They said residue had never freed any space, which was false after a version before 0.0.8 removed a worktree (#70).

Mac app: residue-macos.dmg is the app for macOS 13 or later, on Apple silicon and Intel, with this release's residue inside. It is not notarized yet, so macOS blocks it the first time: the README has the steps to open it.