iTerm2 images live in the cell grid, unlike Kitty placements: repainting
the mosaic behind them erases the picture. Re-emit the image whenever the
mosaic identity (station + track) changes, even if the artwork bytes are
the same.
Also send doNotMoveCursor=1 to iTerm2 itself so the terminal does not
scroll or jump the cursor out from under Textual's compositor; WezTerm
keeps the previous payload since it is pickier about parameters.
beefcarver