Simple as that. I thought I could He-Man the fork to fit the hub as it's only 3 mm on either side. Looks like it requires a bit of force and I'm concerned about breaking something in the long-run; either the frame or the hub.
Which option is best: reduce the hub spacing to 94 mm or widen the fork to 100 mm? And in either case, what's the way to go about it?
The front hub is the top one in the picture below.
Turns out my problem wasn't spreading the fork. It was the fact that the axle diameter was too large for the fork dropouts. I filed the trailing edge of the dropouts and tried again to spread the fork to accommodate the hub. It fit without issue. Pictures below.