The blur is universal, so it would swallow the logo along with everything else. The compositor
now defers every visible brand logo: skipped in both element loops, blitted immediately AFTER
the blur group, before the flash/social/ticker overlays. One logo per scene, so it is cheap.
Preview mirrors it: the staged scene's brand logo is drawn above the blur host (StagedBrandLogo),
so what you see in the editor is what the encoder gets.
Test: a blur covering the logo's area leaves the logo's pixels exactly white while the coloured
background beneath it blends.
