Module transform 

Event-domain geometry and stream algebra — OpenCV-style transforms that operate on the sparse EventStream itself (not a dense frame), preserving per-event timestamps. Every op returns a new stream so calls chain. Coordinates are remapped and rounded — there is no pixel interpolation — and out-of-bounds events are dropped (downscale therefore lets several events share a pixel, which is lossless: representations handle the collisions).

Frame-domain resize lives separately in crate::image; the two are complementary.