Looks like it broke off bending around the stator tooth and did not break off where the winding wire is soldered to the phase wires.
If it did break off at the end of the winding wire, and it didnt break too far, solder all the strands together with a 180/220w Weller iron with the biggest tip available, and some really decent, quality heat sink rated for hotter temperatures of inside the hub motor.
If it’s one strand of solid copper wire bending around the stator tooth, it might be saved, a good Youtube search would be in order because I've never seen that repair done.