PyPlot works but calling matplotlib directly from PyCall aborts

```julia

julia> using PyCall

julia> plt = pyimport("matplotlib.pyplot")
PyObject

julia> x = range(0; stop=2*pi, length=1000); y = sin.(3 * x + 4 * cos.(2 * x));

julia> plt.plot(x, y)
This application failed to start because it could not find or load the Qt platform plugin "windows"
in "".

Reinstalling the application may fix this problem.

```
This causes Julia to terminate abruptly.

Yet using PyPlot works ?

Reproduce the Julia session using PyCall and the direct matplotlib.pyplot import, then compare it with the working PyPlot path. Trace the Qt platform-plugin failure and determine whether the issue needs a PyCall change or an environment-specific workaround; done means direct matplotlib calls no longer abort Julia or the limitation is clearly documented.

Vom Indexierungsmodell aus dem Issue-Text verfasst.