Is it permissible to donate the salary received for not performing work—due to the employing entity's compulsion to do so—to needy patients, or to mosques, or to poor families?

It is inconceivable that the law would allow an employee to receive a full salary without working, especially if residing abroad, as this would be considered tampering with the interests of the country. You do not have the right to this salary, as it is public money that should be spent on the country's interests, and it can be spent on sick people in need of treatment, poor families, mosques, and the like.