Changelog

[Unreleased]

Initial extraction from codechu/cli-py (_term.py), expanded into a public API.
is_tty(stream) — robust isatty() wrapper that never raises.
terminal_size(stream=sys.stderr) — (cols, rows) with fallback ladder: os.get_terminal_size → env COLUMNS/LINES → (80, 24).
capabilities(stream, env=None) — dict of flags (color, truecolor, unicode, emoji, mouse, alt_buffer). Caller passes the env dict explicitly; NO_COLOR and TERM=dumb are honoured.
with_alt_buffer(stream=sys.stdout) — context manager emitting \x1b[?1049h on enter and \x1b[?1049l on exit.
with_raw_mode(fd=sys.stdin.fileno()) — context manager using termios for char-by-char input. POSIX only.
on_resize(callback) — install a SIGWINCH handler; returns a remover function that restores the previous handler. POSIX only.
hide_cursor(stream) / show_cursor(stream) — emit \x1b[?25l / \x1b[?25h.
clear_line(stream) / clear_screen(stream) — emit \x1b[2K\r / \x1b[2J\x1b[H.