Faster macOS runner provisioning on Tuist Cloud via golden base cloning

macOS runner VMs on Tuist Cloud are now provisioned from a per-host “golden” base VM via a local APFS clone instead of re-downloading the ~40 GB macOS+Xcode image on every single-shot recycle. Combined with image-aware pod scheduling that steers jobs toward hosts that already hold the matching golden, median macOS job provisioning drops from about 7 minutes to seconds, idle hosts reuse their cached image across bursts (24h golden retention), and steady-state concurrent macOS builds on the fleet climb from roughly 4 toward the full 9-host budget. Users running macOS builds on Tuist Cloud should see jobs start almost immediately when the image is already on the host, instead of waiting through a multi-GB pull per recycle.