fix: Add Windows support to python_repl tool (#15)

[Eng-Ahmd]

fix: Add Windows support to python_repl tool (#15)

Make python_repl tool cross-platform compatible to work on Windows, Linux, and macOS.

Problem

The original implementation relied on POSIX-specific features that are not available on Windows:

• PTY operations (pty.openpty(), os.fork())
• POSIX signals (SIGTERM, SIGKILL)
• File descriptor operations (fcntl, termios, select)

This made the tool completely non-functional for Windows users.

Solution

Implemented a cross-platform execution strategy:

Core Changes:

1. Platform Detection

   • Added IS_WINDOWS and IS_POSIX flags using platform.system()
   • Conditional imports for POSIX-only modules to prevent import errors on Windows

2. New SubprocessExecutor Class

   • Cross-platform alternative using subprocess.Popen with pipes
   • Maintains state persistence through temporary script files
   • Handles output streaming with proper text encoding for Windows
   • Thread-safe output capture and cleanup

3. Preserved PtyManager for Unix

   • Wrapped existing PtyManager in if IS_POSIX: conditional
   • No changes to Unix/Linux/macOS functionality
   • Maintains superior interactive PTY experience on POSIX systems

4. Execution Logic

   • Windows: Uses SubprocessExecutor for all modes
   • Unix interactive: Uses PtyManager (original behavior)
   • Unix non-interactive: Uses direct execution (original behavior)
   • Graceful fallback ensures code always executes

Technical Details:

• State persistence works identically across all platforms using dill
• Output capture and ANSI cleaning preserved
• Error handling and logging maintained
• User confirmation flow unchanged
• All safety features retained

Backward Compatibility:

• Zero breaking changes for Unix/Linux/macOS users
• PTY mode still used by default on POSIX systems
• All existing features and behaviors preserved

Testing:

Verified on:

• Windows 11

Closes #15