What are the days of fasting and prayer that must be made up, considering the discharge of brown and red spotting on the aforementioned days?

Scholars differ regarding the brownish discharge (kudra) before menstruation. Some consider it menses if it is followed by blood, while others add the condition of menstrual pain, which is the more apparent view. And some do not consider it menses at all.

The blood that precedes menstruation is considered menses, and it is obligatory to make up the fast of the day on which the blood appeared.

The brownish discharge that occurred in Ramadan until the 10th of Shawwal was not menses, especially if it was not accompanied by menstrual pain. Therefore, your fasting in Ramadan is valid, and you only need to make up the fast of the 28th.

If the brownish discharge is accompanied by menstrual pain, or if it occurs at the usual time of menstruation, then it is menses, and the woman must make up the fasts she observed during that period.