FPC's GetAppConfigDir on Windows falls back to the exe directory
if the shell API call fails, which breaks installs in Program Files.
Read %APPDATA% from the environment variable instead.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Program Files is read-only for normal users; GetAppConfigDir(False)
returns the proper per-user config location on all platforms.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>