OneDrive: Sync support for up to 1 million items on macOS

<p>OneDrive Sync supports syncing up to 1 million items on macOS devices, helping teams manage large document libraries and shared content at scale without compromising access across devices. This preview requires the Insiders ring and that devices meet minimum hardware and configuration requirements. Devices that don't meet these requirements continue to sync at the existing 300,000-item supported limit with no disruption.</p>