115 is an odd fork width. I think you mean the fork is spec'd to fit a 15x110mm "Boost" hub? And the hub on your front wheel is 15x100mm.
If that's the case, you can definitely adapt the hub to fit the fork. You need two axle spacers, a 15x110mm axle, and a spacer to shift the brake disc into the correct position. Problem Solvers actually sells the spacers in a kit...
For 6-bolt brake discs: https://problemsolversbike.com/products/booster-front-hub-spacing-kit-6-bolt
For center lock brake discs: https://problemsolversbike.com/products/booster-hub-spacing-kit-center-lock-front
The real question is: where tf did you get a free Flight Attendant fork?!
Edit: if you really want to go down the rabbit hole and design your own spacers, SRAM publishes everything you need in their frame fit specifications:
https://www.sram.com/globalassets/document-hierarchy/frame-fit-specifications/road/2024-road-frame-fit-specifications.pdf