What is the ruling on performing Hajj and building mosques with salaries received from police and military jobs in the current Afghan government, or from internal and external institutions within it?

There is no objection to a Muslim working as a policeman or in public services if they are permissible. It is permissible to benefit from what is earned from such work for Hajj or donating to mosques and the like. However, the worker must be careful not to assist an oppressor in his oppression.