The CONV2D images are saved BEFORE synth injection (real-only), so the actual
DNN input (LoG-conditioned real bg + injected synth) was no longer visible once
the mixing order moved to post-conditioning. Add a per-selected-level save of
dpixels_pyramid right after injection: getBaseName()+"-SYNTHMIX"+("B" if over
real bg)+("-SUBAVG" if avg-subtracted)+"-LEVn", full-frame (640x512), same
timestamps - what the network actually sees. Gated by save_LoG_pixels.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>