Is it permissible to make a fictitious contract for one's wife abroad in order to obtain a work leave as an accompanying spouse, given the weak scientific capabilities in the country, knowing that this contract does not involve bribery and does not affect anyone's rights?

If your employment contract does not allow for unpaid leave, then it is impermissible to forge an employment contract for your wife and claim to be accompanying her in order to obtain leave, due to the falsehood involved and the violation of the contract terms. Lying is forbidden and is among the worst of ethics. The Prophet, peace and blessings be upon him, said: "Muslims are bound by their conditions." Therefore, either you pursue a permissible path for travel and work abroad, or you resign from your job.