CV Components Touching Border

Keeps every connected component of a binary mask that reaches a chosen image edge - or, with mode = 'remove', everything that does NOT. Touching the frame edge is what separates unbounded background (sky, a table surface, water) from bounded objects, and the inverse is the usual way to drop detections the frame clipped. Neither 'Keep Largest Component' nor 'Select Component At Point' can express it: the largest blob is often something else entirely, and one probe point catches one component, while a background region is routinely cut into many by whatever crosses it. Failure-tolerant: an empty mask (or one where nothing touches the chosen edge) yields an empty mask and found=false, not an error.