hf_weight_export
Per-module quantized weight export.
The leaf of the export pipeline: packing one module’s weight into its quantized representation and registering the scale buffers beside it, plus the registry dispatch and the whole-model walk that drive it.
Like hf_export_prep, this imports only leaf helpers (model_config, quant_utils,
registry) and never an exporter, so the exporters and the MoE/handler plugins can import
it directly instead of lazily.