Is it permissible for an employee who works in a company that provides alcohol to foreigners, and is sometimes forced to give it to Muslim officials as a bribe, to continue in his job? And is he entitled to claim his financial dues if he leaves?

What you mentioned includes many sins and errors that a Muslim should not commit. The carrier of alcohol and the one who pours it are both cursed, just as the briber, the bribed, and the intermediary are cursed. The sin is compounded by giving alcohol to Muslim officials in exchange for overlooking security or health violations. What is obligatory upon you is to repent and abandon this profession.