Root cause: TransitionImageLayoutDepth used LayerCount=1, so only
layer 0 of the 6-layer cubemap was transitioned to ShaderReadOnlyOptimal.
Layers 1-5 stayed in Undefined/DepthStencilAttachmentOptimal → sampling
returned garbage → no shadows on surfaces facing those directions.
Fix: added layerCount parameter to TransitionImageLayoutDepth (default=1).
Shadow cubemap transitions use layerCount=6.
emil28092005
a572f9d360