Enable CLI Usage on Windows

[nickmccarty]

Summary

On Windows, no colab command runs at all — not just console. console.py imports the POSIX-only termios/tty modules at module top level, and because commands/execution.py does from colab_cli.console import connect_console at load time, the import chain fails before Typer ever dispatches a subcommand. Even colab -h crashes.

Environment

• OS: Windows 11 (native, not WSL)
• google-colab-cli 0.6.0 (from PyPI)
• CPython 3.12 / 3.13

Repro

> colab -h

Traceback (most recent call last):
  ...
  File "...\colab_cli\cli.py", line 26, in <module>
    from colab_cli.commands import session, execution, files, automation, run, utility
  File "...\colab_cli\commands\execution.py", line 29, in <module>
    from colab_cli.console import connect_console
  File "...\colab_cli\console.py", line 20, in <module>
    import termios
ModuleNotFoundError: No module named 'termios'

(import colab_cli.cli reproduces it directly, no CLI invocation needed.)

Root cause

console.py unconditionally does import termios / import tty at the top. These modules are Unix-only. They're only actually used inside connect_console, and only on a real POSIX TTY (raw-mode setup + SIGWINCH). So the top-level import is the only thing preventing the CLI from working on Windows — the rest of the surface (new, exec, run, sessions, install, …) has no POSIX dependency.

Suggested fix

Guard the imports and only take the raw-terminal path when those modules are present. Piped/agent usage sets is_tty=False and never touches them, so behavior is unchanged everywhere it works today; interactive colab console on Windows would fall back to line-buffered input instead of crashing.

try:
    import termios
    import tty
    _POSIX_TTY = True
except ImportError:  # Windows
    termios = None
    tty = None
    _POSIX_TTY = False

Then in connect_console:

is_tty = sys.stdin.isatty()
raw_mode = is_tty and _POSIX_TTY
fd = sys.stdin.fileno() if raw_mode else None
old_settings = termios.tcgetattr(fd) if raw_mode else None
...
if raw_mode:
    tty.setraw(fd, termios.TCSANOW)
    if hasattr(signal, "SIGWINCH"):
        signal.signal(signal.SIGWINCH, handle_sigwinch)
...
finally:
    if raw_mode:
        termios.tcsetattr(fd, termios.TCSANOW, old_settings)
        if hasattr(signal, "SIGWINCH"):
            signal.signal(signal.SIGWINCH, signal.SIG_DFL)

I applied this locally and confirmed native Windows then works end-to-end (colab -h, ADC auth, and a colab run CPU one-shot against a real Colab VM). Happy to share more detail if useful -- in the meantime, thank you for all your efforts!