Example plugin for fizzy adding a ghostty terminal to the bottom panel
Other plugins run a program in a terminal the person types into through the internal command
terminal.run (the chat's terminal sign-in, claude /login, is one). Its arguments, as ZON:
.{ .title, .argv, .env = .{ .{ .name, .value } }, .cwd, .done, .tag }. The program runs in a
pane of its own in the bottom panel, in cwd (empty: the project folder), over fizzy's
environment with the login shell's PATH plus env. When it exits, terminal.run calls the
command done with .{ .tag, .code }; the pane stays, showing the exit code, until the person
closes it. A caller checks host.hasCommand("terminal.run") before offering anything that needs
it. The contract is src/launch.zig.