The win32 tier is exactly the koffi IFileOpenDialog child process; any failure surfaces as-is. The pwsh -> Windows PowerShell 5.1 cascade, the shared WinForms script, and the triple-miss AggregateError are deleted: koffi is a packaged dependency whose availability the install guarantees, so no mechanism fallback exists (the browse backend remains the fallback at the composition level). The pwsh-first DPI picker-fix note is consolidated into a new simplification note recording the reversal.
xjt