Probe generated canaries after mountVersion and always readActive for
prefixed caches so sprites are not blanked by empty PhysFS stubs.
Co-authored-by: Cursor <cursoragent@cursor.com>
NX Play for Blue failed because mountVersion relied on absolute
PHYSFS_mount first. Prefer love.filesystem.mount of blue|yellow, overlay
generated trees by version prefix, and align CacheFs.prefix in bootGame.
Co-authored-by: Cursor <cursoragent@cursor.com>