The ornamental design for a snap-closure beanie, as shown and described.
FIG. 1 is a front perspective view of a snap-closure beanie showing the design in a position of use;
FIG. 2 is a right side view thereof;
FIG. 3 is a rear view thereof shown with the snap-closure in a closed position; and,
FIG. 4 is a left side view thereof.
The human figure drawn in broken lines is environment included to show the snap-closure beanie in a position of use and forms no part of the claimed design. FIGS. 1 and 3 show the design on an adult size figure and FIGS. 2 and 4 show the design on a youth size figure.