Here is some of the knowledge that I have gained over 10 years of maybe buying a meal from a resort like 10 times.
-Ramen noodles.If they get crushed just use less water and you are set. If you are wearing a pack and you don't want them to get crushed, put it in a crush proof sandwich container.
-Beef jerky. Pretty expensive, but you can make your own and if you do it right it is pretty good. high protein and pack-able.
-Instant oatmeal packets. The paper packets that they come in aren't water permeable so you don't need a container to make them in, just shake the packet up and pour hot water right in and stir. proof:
-Instead of sandwich bread use pita bread, just stuff it with turkey, ham, salami, or whatever and since pita is unleavened, it can't get smashed and soggy. Super easy to eat with gloves on riding up the lift so you don't have to deal with crowds in the cafeteria. Very slim so you can fit it in a jacket pocket. Also try with nutella for a morning snack. Warm up the pita in the microwave(like 10 seconds) when you make it and it is less likely to rip.
-Emergen-C packets are pretty similar to sports drinks, but better nutrients and vitamins. I have never tried the sport drink version, but it just has electrolytes and shit like that. Again very pack-able and lightweight.
-Someone else said it already, but Hard boiled eggs are good too. High in protein and small, but not necessarily slim and pack-able, maybe if you slice them up though
-Every once in a while treat yourself to a meal bought from the resort. It helps to support the guys that make you ski day possible. A lot of resorts have really good food, and while it may seem overpriced is is actually pretty good for the price. A-Basin's Black Mountain Lodge pastrami sandwich tastes like a $25 dollar sandwich for $14(i think).