quantize_dit_int8wo.py builds the offline W8A16 artifact (per-channel
symmetric int8, pack-quantized via compressed-tensors' own packer,
per-component config wrapper so encoder/VAE stay BF16, digest manifest);
serve.sh/probe.py/gate.py/psnr.py adapt the issue-2 kit for the
structure-gated capacity matrix (1-4 refs x seeds 2301-2304).
