Darkshell (`dsh`) on Windows vs Unix

Signals and interrupts

Unix / Linux: When running an external command, Darkshell installs a Ctrl+C handler that requests the running child process group to terminate. At the interactive prompt, rustyline handles line editing; interrupt during prompt cancels the current line.
Windows: Console control events (Ctrl+C) are best-effort. Child processes are terminated without full Unix-style process-group semantics. Interactive line editing uses the same rustyline backend; behavior may differ slightly depending on the terminal (Windows Terminal, ConPTY, legacy console).

Bash-style job control (Ctrl+Z, fg, bg, % job ids) is not implemented on any platform in v0. Background & starts a detached child on a best-effort basis; do not rely on POSIX job control semantics on Windows.

cd and pwd use Rust’s std::env::{set_current_dir, current_dir} and normalize paths per the OS.
HOME is used when available; on Windows, USERPROFILE is accepted as a fallback for cd with no arguments.

Startup: ~/.dshrc (or %USERPROFILE%\.dshrc) is sourced when the REPL starts, if the file exists.
History: ~/.dsh_history (or %USERPROFILE%\.dsh_history) persists command history between sessions.