How can the Hadith "The Hour will not be established except upon the worst of people" be reconciled with the Hadith "Seven are those whom Allah will shade with His Shade on the Day when there is no shade except His Shade"?

There is no contradiction between the two hadiths. The first describes the state of people when the Hour commences, stating that it will not occur except upon the worst of people, after Allah has taken the souls of the believers with a pleasant breeze. As for the second, it pertains to the Day of Resurrection, describing the honor and glad tidings Allah has prepared for seven categories of people, by shading them under His shade or the shade of His Throne.