The ornamental design for a hairweft, as shown and described.
FIG. 1 is a perspective view of the hair weft showing my new design.
FIG. 2 is a front view thereof.
FIG. 3 is a back view thereof.
FIG. 4 is a left side view thereof.
FIG. 5 is a right side view thereof.
FIG. 6 is a top view thereof; and,
FIG. 7 is a bottom view thereof.
The hair weft is shown with a symbolic break in its length. The appearance of any portion of the article between the break lines forms no part of the claimed design.