Mac release notes.

Preserves relative symbolic links and POSIX permissions during Mac-to-Mac file transfers; fixes incomplete app and framework transfers; adds optional clipboard update notifications; blocks concealed and transient clipboard data; and improves cleanup for failed or cancelled transfers.

Improved Windows-to-Mac Finder file transfers, paste marker cleanup, file conflict handling, transfer error reporting, duplicate-device discovery, and receiver-side progress display.

Initial public preview for macOS with local-network clipboard sharing and Sparkle updates.