Is it permissible for a woman to combine the intention of reading the Qur’an to fulfill her vow with the intention of completing a full recitation (khatm), and must she make up the Istikhara prayer that she vowed for the days of menstruation during which she was unable to read, knowing that she now reads the Qur’an during menstruation using a barrier?

The vow is valid and binding, and it must be fulfilled, as the Prophet, peace and blessings be upon him, said: "Whoever vows to obey Allah, let him obey Him." You must recite the vowed amount even if you are menstruating, as recitation for a menstruating woman is permissible according to the preponderant opinion. And even if we were to say it is forbidden, the vowed recitation is obligatory, and what is forbidden for her is only voluntary recitation. You must intend the vowed recitation. It is not prescribed for you to pray the two rak'ahs of repentance, because they are prescribed when committing a sin.