For non 96 DPI taskbar icon (SetupIconFile) during install is blurred(stretched?)
I'm not sure, but I'm sure ico file has all possible icons in it: 16/32 bit + all sizes from 16x16 to 256x256.
Same icon works well in my application with all DPI.
Windows 7
120 (144) DPI
http://www.filedropper.com/test_27 - icon
Setup and application running simultaneously:
For 125% zoom (120 DPI) you need 40x40 icon (= 32x32 * 125%)
If you do not have one, the Inno Setup will probably use upscaled 32x32 icon.
Your application seems to use a different strategy, maybe downscaling 48x48 icon.
Not sure why you should have problem on 150% zoom (144 DPI), as you have 48x48 icon (= 32x32 * 150%).
I've tested your icon in a simple installer and it indeed shows a nice icon on 150% zoom (tested on Windows 7).
In my installer, I have an .ico file with these sizes: 16, 20, 24, 32, 40, 48, 60, 64.
This nicely covers all needs for up to 200% zoom (192 DPI).
Also, it's possible that there is a difference between Ansi and Unicode versions of Inno Setup. They are based on different versions of Delphi, possibly using different strategies for selecting the icon. That may explain why you have problems on 150% zoom, while I do not.
I'm using Unicode version, which is based on over a decade newer version of Delphi (Delphi 2009 vs. Delphi 2 from 1996).
