macOS GUI pkg: Fresh wrapper overwrites fresh binary

The macOS GUI pkg is broken. In create-app-bundle.sh line 40, a wrapper named Fresh is written to Contents/MacOS/, but the real fresh binary was already copied there. macOS is case-insensitive by default, so Fresh and fresh are the same file — the wrapper overwrites the binary. After install you only get a script named fresh, no real binary left, so it can't launch.