Do a woman's feet constitute 'awrah (parts that must be covered) according to the Maliki school, and are there clear hadiths supporting this, taking into consideration the difficulty women face in covering them in summer?

A woman is obligated to cover her feet both in prayer and outside of it, based on what was reported in Sunan Abi Dawud from Umm Salamah (may Allah be pleased with her) that she asked the Prophet (peace be upon him): "Can a woman pray in a dir’ (a long dress) and a khimar (head covering) without an izar (lower garment)? He replied: 'If the dir’ is ample enough to cover the back of her feet.'"