What is the ruling of Islamic law on concealing the truth about a rape incident and the loss of virginity from the husband, and what is the ruling on the husband's actions of demanding the waiver of financial entitlements, taking the dowry, and threatening the family with filing a lawsuit?

You are not required to inform your husband about the rape unless he stipulated virginity. It is not permissible to restore the hymen. Your husband should have kept you kindly if he saw nothing suspicious in you, and not forced you to relinquish your rights. You can resort to the Sharia courts to redress the injustice. If your husband divorces you, Allah may compensate you with something better. If your repentance and righteousness are sincere, Allah will not abandon you.