install.sh now covers every common Linux distro (apt, dnf, yum, pacman,
zypper, apk, xbps), macOS on arm64/x86_64, and hands off to install.ps1
under Git Bash. install.ps1 + install.cmd give Windows a double-click.
Autostart: systemd user unit on Linux, launchd on macOS, Task Scheduler
on Windows. A terminal guides the role choice and the first key or bot;
agents get --print JSON and ANYBOT_NONINTERACTIVE=1 with env seeding.
`加一台電腦` shows the Windows and the Mac/Linux line together.