TerminalSession class

Manages terminal session state (cursor visibility, raw mode).

This is a composable component that can be used:

• Directly for display views that need cursor control
• As part of PromptRunner for interactive prompts

For display views (no key input needed):

final session = TerminalSession(hideCursor: true);
final out = RenderOutput();

session.run(() {
  out.writeln('Loading...');
  // ... do work ...
  out.clear();
  out.writeln('Done!');
});