(My question is related to Rear disc brake rotor rubbing against caliper frame mount? but I hope to provide some more context & photos.)
I have a Rocky Mountain Edge mountain bike (possibly 2011 or 2012) that has factory-installed Shimano hydraulic disc brakes. I was replacing a flat front tire today and had trouble getting the rotor aligned inside the caliper. When I took a closer look, I was surprised to see that the disc has been rubbing against the front fork mounting bracket along at least half of its radius.
This photo shows the wear to the mounting bracket and the caliper support (there is corresponding wear on the rotor):
(n.b. the bike was upside down when this photo was taken: dropouts are on the left, and the rear of the bike is toward the right.)
To me, it seems like there's an issue with where the wheel sits relative to the fork (i.e. that it's a few millimetres too close to the caliper side). The rotor seems to be permanently affixed to the wheel (no screws), and it doesn't appear to have moved relative to the hub. Looking at the quick-release skewer, it seems like all the parts are there, but it still doesn't sit properly.
How can I solve this problem? Is there a spacer I can add to the quick-release skewer so the rotor sits the proper distance from the fork? Is there a specific offset for this type of brake caliper?
Is it likely to be caused by a damaged wheel? (The rim is quite out of shape, so I could use this as an opportunity to replace the whole wheel.)
EDIT: some more photos: