Fixes#58807. A compressed-tensors pack-quantized checkpoint that ships
its MTP head dense (plain mtp.*.weight names in a separate bf16 shard)
crashes at weight load: Qwen3_5MultiTokenPredictor builds its Linears
from the target quant config, so the loader expects packed names
(weight_packed) the checkpoint never had, and the weight-map walk dies
with "no module or parameter named fc.weight".
Detect the dense MTP head from the checkpoint itself: read the
safetensors index via the same repo-file channel used for recipe.yaml
(local cache first, Hub download as fallback). If any mtp.* tensor
carries a quantization artifact suffix the head is properly quantized
and nothing changes; if every mtp.* entry is a plain .weight the whole
predictor builds unquantized (fc and layers), mirroring the existing
modelopt_fp4 and GPTQ dynamic carve-outs. Single-file checkpoints have
no index and keep current behavior; NVFP4 checkpoints are unaffected
(their mtp.layers.* carry artifacts).
Co-Authored-By: Hinata <hinata@idihore.id>
Signed-off-by: MOVZX <movzx@yahoo.com>
MOVZXandHinata
5af48b498c