As an owner who has had 2 horses with varying degrees of laminits/founder, they most assuredly are salvagable if the rotation isn't too severe. My old QH had laminitis most of his life, we watched his diet very carefully and limited his grazing. Mainly, he'd have flares only once or twice a year at most, and we treated the discomfort from that with bute. We continued riding him until he let us know it was time to quit, at 30 y.o..
The 2nd horse was more severe, she was a broodmare and we sent her out to be bred one year and the breeding barn's staff made a feed error (she got no grain due to her laminitis and they fed her a warmblood's grain ration) and she had severe gas colic. Due to fearing for their jobs, they said nothing for over 12 hrs, and by the time I went to get her and take her to the vet, she was in such severe pain that she was already starting to founder. The colic was severe but remedied fairly quickly. The founder however, kept her in ICU for 10 days and we thought we'd lose her to that. Both front feet rotated, right more than left, 7 degrees for the right, I think 3 for the left. That was in 2005. She was 25 at the time. She came back from it, and with careful trimming and careful diet management, she did totally fine. She was retired from being a broodie at that point, and was just a pasture puff until last winter when she was injured in a pasture accident. Basically, she hurt her left leg to the extent that she'd have required extensive stall rest and would have stressed her right leg/foot even more so we pretty much decided it was put her down now or put her down later. At the time we put her down in Feb, her right front foot sole was so thin you could feel the coffin bone and we knew if she had another big flare, it would descend through the sole. So at 31 years, we let her go.
Neither horse was expensive to manage and except for brief flares of a couple of days, neither was in pain most of the time. Lucky passed at 32 y.o. and Fetyszka passed at 31, so both lived full lives and knew they were loved and cared for. Only you can know what is right for your horse, so if the rotation/pain is severe enough, putting her down is certainly and option. You don't say how old she is, so I can't tell you what I might consider/try in your case, nor do you say how severe the rotation is, if any.
When you say 'early stages of founder', to me that means more of a laminitis flare up than that she actually foundered. Founder itself is usually pretty dramatic. Fetyszka's rotation was not considered terribly severe yet she went down and stayed down for 8 days. When she got up she was bedded on peat moss and then sand for over a month until she showed signs of being more comfortable in her stance.
Hope some of this helps you in your decision process.
