Add install-remote.sh, which fetches the latest release and runs its
install.sh so setup no longer needs a git clone. The popup now probes
the native host with a "ping" action on open and, if it's not
registered yet, shows the one-liner (with copy-to-clipboard) instead
of the auto-capture toggle -- so a Web Store install can be completed
end-to-end by clicking the extension icon and pasting one command.
