Like others, you may need to re-enter the file extension to open it. At the time of the save-under replace "htm" with "sldprt" in the case of this question.
The problem comes first and foremost from the peak. If you cut it, you can make a 0.1mm shell. Then you also have to play with your radius which must be of a value of less than 2.5mm.
Use Tools/Check, check "Minimum Bend Radius" and then click "Check". It tells you "Face (min. radius,1)". Click on this message and an arrow will tell you where the mini radius is.
Look at the attached file, there are 2 configs:
_Défaut, cut tip and 0.1mm shell
_2.5, cut tip and partly cut piece with 2.5mm shell
By having a diamond point at the top of your piece, the shell will never fit as it is.
So you have to make your part first then the hull and then your interior and exterior leaves.
You also have the possibility to make the inner shape of your shell by surface and then make a surface shift, close this set of surfaces and then fill the volume with material.