Does a woman's sleeping after Maghrib and waking up for Isha prayer at its permissible time fall under the disliked act of sleeping after Maghrib, and does the time for Fajr end with the appearance of light?

The time for Fajr ends at sunrise according to the majority of jurists. It is reprehensible to delay it without an excuse until after Isfar, which is the whiteness of the day before sunrise, and it may even be forbidden. However, if a worshiper sleeps until the time of Isfar, there is no harm in performing it then.