What did Christ—or rather, Mashiach—mean to the original Jews who were actually His disciples?
It meant that they could return to Judea and rebuild the Temple with the full backing of the Persian empire. See Isaiah 45:1 ("Thus said the Lord to his Messiah (Maschichu = his Messiah), to Cyrus, whose right hand I have holden to subdue nations.")
Mashiach just means an individual anointed by God to fulfill a particular purpose. It had no connotations of divinity before Pauline Christianity.