Progress bar should determine terminal width using the specified out stream

Redirecting stdout and printing progress on stderr should determine the correct terminal size. At the moment the terminal size is only calculated correctly if stdout is a tty. Stderr should be used a fallback for that calculation.

The terminal width detection logic is likely in a module handling TTY checks, such as `src/term.rs` or similar. Look for functions that get terminal size, possibly using `libc` or a crate like `termion` or `console`. The fix involves checking if the primary output stream (stdout) is a TTY, and if not, falling back to checking stderr. Run the existing tests to ensure the progress bar still renders correctly in different redirection scenarios.

Scritto dal modello di indicizzazione a partire dal testo della issue.