connect stdin of external commands to the terminal

Without Stdin, commands read from /dev/null, so interactive programs
like 'sudo su -', vim or ssh got EOF right away.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

main.go

@@ -760,9 +760,13 @@ Features:
 	// Prepare the command to execute.
 	cmd := exec.Command(args[0], args[1:]...)
 
-	// Set the correct output device.
-	cmd.Stderr = os.Stderr
+	// Connect the command to the terminal. Without Stdin the command would
+	// read from /dev/null, so interactive programs (su, vim, ssh, ...) would
+	// get EOF right away. readline only reads from stdin while a line is
+	// being edited, so it does not steal input from the command.
+	cmd.Stdin = os.Stdin
 	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
 
 	// Execute the command return the error.
 	return cmd.Run()