* fix(vfs): tolerate fsync ENOTTY/EINVAL on filesystems without fsync
virtio-fs (macOS VMs) answers fsync/F_FULLFSYNC with "Inappropriate
ioctl for device" (os error 25), failing the whole atomic write. The
write itself already went through, so degrade like SQLite: log and
continue to the rename instead of propagating.
* fix(vcs): tolerate filesystems without fsync when updating ignore files