Elliptical orbit and varying sunlight intensity.
For reference: how it works on Earth.
Usually summer is warmer and I think on earth that is a direct function of day length which is longer ins summer; the reverse is true in winter.
The OP wants "summer" that has long nights, with more time for summer dreams, ripped at the seams. OP requests "winter" that has long days. I am going to assume that summer means it is warm and winter means it is cool. We will accomplish this with an elliptical orbit.
Don't watch that elliptical orbit gif too close or you will look up and 3 hours will have gone by.
Considered from the perspective of the Arctic: long days coincide with the furthest extent of the orbit. Days are long but the sun is distant so things stay cool: I am calling this winter because it is cool. The reverse happens in "summer". Days are short in the Arctic because it is tipped away from the sun but it is close and so sunlight is stronger.
The reverse would be true in the antarctic: scorching hot summers with long days and freezing winters with long nights.
Other aspects of the OP I consider red herrings. But I worry about that Dailey downvote if those criteria are not included somehow. So: there is another planet exactly like this one in the system. Both of these planets rotate so as to have 48 hour days.