Klixon self resetting or manual reset unit,or thermal non resettable cut out attached to the resistor. The one time thermal fuse is easy to attach with a small slide on sleeve of silicone coated fibreglass sleeving, and will both provide insulation and good thermal coupling. you typically choose a thermal fuse of around 110C, so that it will not fail in normal use, with the resistor typically reaching 70C surface temperature in the 15 seconds of on, and with the heat soak after. Longer time on it will reach the 110C point and the thermal cutout will melt, most likely after around 5 minutes.
A fuse is not good, it will be replaced with another of different rating, or will be replaced with one not of the same brand, with different trip characteristics, or will be wrapped in foil. You can get small thermal cutouts that will provide protection that are the same size as the one time unit, but they need the non resettable unit as back up as well. Thermal fuse is both rugged, reliable ( they will melt at rated temperature, with up to 5C below it as margin, and will never fail to operate) and cheap, plus needs minimal extra protection, other than a regular fuse to protect the rest of the circuit and wiring from faults, probably here a 1A slow blow fuse.