Measured on a PS5 (firmware 13.60): before scePadInit the call returns
NOT_INITIALIZED (0x80920005); after it, a mode of 0 or below returns
INVALID_ARG before the handle is checked, and a bad handle with a
higher mode returns INVALID_HANDLE.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>