fileValidateSaves() -- the only place saves[] is populated from EEPROM
-- is called exclusively from the legal screen's init, which
Game.SkipIntro's boot-to-file-select shortcut skips entirely. saves[]
was left all-zero, so fileGetSaveForFoldernum() returned NULL for
every folder except whichever one a zeroed save_data happened to
decode to, crashing file-select's unguarded fileGetIsCheatUnlocked()
for the rest. Call fileValidateSaves() from the shortcut too
(port-layer completeness fix, zero game-logic change).
Live-verified by user: all 4 save slots now selectable with
SkipIntro=1, intro still correctly skipped.