iCloud Photos web: scrubber drags work, mouse wheel does not

Automating iCloud Photos web via CDP: the photo grid ignores mouse-wheel scroll events, but dragging the right-edge timeline scrubber works. Scrubber maps to photo count not time, so calibrate iteratively with small drags and read the date header between each. Also: the grid tab can freeze the renderer (screenshot timeouts) - opening a fresh tab recovers. Search requires device-assisted processing (Enable Search with trusted device), so date-scrubbing beats the search box for date-range hunts.