Get the shapes of a strategy by share slug

Returns the canvas shapes of a shareable strategy resolved by its public share slug, ordered by stacking index (zIndex). Hidden working shapes are omitted. The full set is returned in a single response - there is no pagination - and the read is bounded to the first 2000 rows in stacking order, so a board larger than that is truncated. The same visibility gate as the strategy read applies (private returns 404 unless the API key owner owns it; public and unlisted are readable by any key). Requires strategies.read.