When did scholars begin to use the term "Salat al-Ibrahimiyya" (Abrahamic Prayer) to refer to the second half of the Tashahhud? Was this usage known to the Prophet (peace be upon him), or to the Companions and their successors, or was it a later innovation by scholars? If so, when?

The term "Salat al-Ibrahimiya" (Ibrahimic Prayer) was not reported from the Prophet (peace be upon him), nor from his companions or the Tabi'in. The earliest person to use it was Imam Ibn al-Qayyim, who passed away in 751 AH, in his book "Zad al-Ma'ad," where he described it as the most complete form of prayer upon the Prophet (peace be upon him).