Lima v2.1: macOS guests and enhanced AI agent safety

Lima v2.1 (currently in beta, GA at KubeCon) brings experimental macOS and FreeBSD guest support, plus a new AI agent safety feature. The `limactl shell --sync` command lets developers run AI agents like Claude or Aider against a fully isolated VM copy of their files, presenting an interactive diff before any changes are applied to the host. Performance improvements include a guestagent binary size reduction from 14MB to 6.1MB, disk consolidation into a single file, and improved host-to-guest time sync. Other additions include a `limactl watch` command, multi-node k3s cluster support, and guest directory path standardization.