There is work, but it is flow work, not external work. Remember, our control volume is defined by a set of streamlines. Between the inlet and the outlet of the streamlines the velocity of the flow changes, but it does this without heat transfer and without external work. Remember work is the transfer of energy across a system boundary . It is when it crosses the system boundary that we label and identify it.
Fluids stagnate on every surface they meet.
Read the explanation given in the notes. If it is still unclear, please let me know. I am unclear as to why the leading edge of the wing heats up in the first example, then later you said temperature drops over the wing causing the condensation trails. This is a very good question. It does get hotter and colder at the same time.