The win32 branch now spawns pwsh.exe (PowerShell 7) first and falls back
to powershell.exe (Windows PowerShell 5.1) only when pwsh is missing
(ENOENT), mirroring the Zenity-KDialog fallback. PowerShell 7 renders the
modern IFileDialog folder picker; the 5.1 fallback keeps the legacy tree
functional. Both runtimes execute the identical script, which opts the
process into system DPI awareness (SetProcessDPIAware) before any window
exists, fixing the blurry bitmap-stretched dialog on scaled displays.