Definition of direct flights

I'm uncertain if my flight itinerary is eligible for the 144 hours free stay?

I'm flying from Prague to Shanghai with an airport layover in Xi'an Xianyang (1hour 35min) and 5 days later from Shanghai to Seoul. All the flights are on the same ticket from China Eastern.

Is my first flight considered a direct flight or is the fact that I change planes in Xi'an already a transit?
Would I have to do all the immigration already in Xi'an?

In this case the 1,5 hours would be not enough