The v0.1.2 fix that forced Qt's non-native dialog for the "open test"
dialog only covered one call site. The same XDG-portal-vs-sibling-files
problem applies to every other QFileDialog in the GUI (save report,
log file path, default report/log dirs in preferences, python/lua
interpreter pickers).
Extracted a single ``file_dialog.options()`` helper in main_win/ and
threaded it through every getOpenFileName / getSaveFileName /
getExistingDirectory call in main_win/. Outside Flatpak the helper
returns an empty Options(), so the native dialog stays in use on
KDE / GNOME / Windows / macOS.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
