[Issue]: [CK][CK BUILDER] CK Builder missing DeviceGroupedConvBwdWeight_Explicit support #4940

Problem Description

The builder cannot construct DeviceGroupedConvBwdWeight_Explicit instances. The CK instance library ships ~24 .cpp files instantiating these in its bwd weight conv factory, but the builder has no path to them.

DeviceGroupedConvBwdWeight_Explicit (include/ck/tensor_operation/gpu/device/impl/device_grouped_conv_bwd_weight_explicit.hpp) wraps a batched GEMM V3 op to perform 1x1/stride-1/pad-0 backward weight convolutions as explicit GEMM. It has an optional two-stage path with workspace when sizeof(WeiDataType) % 4 != 0. Covers FP16/BF16, 2D and 3D, NHWGC-family layouts only.

The instantiation chain is:

1. GEMM config tuples defined in .hpp headers (device_exp_gemm_xdl_universal_km_kn_mn_instance.hpp, device_exp_gemm_wmma_universal_km_kn_mn_instance.hpp)
2. .cpp files under library/src/tensor_operation_instance/gpu/grouped_convnd_bwd_weight/explicit_xdl/ and explicit_wmma/ call add_explicit_gemm_device_operation_instances() with those tuples to register concrete instances (15 XDL, 6 WMMA, 3 odd-dimension variants)

Operating System

All OSes

CPU

All CPUs

GPU

All GPUs

ROCm Version

ROCm 7.x

ROCm Component

composable_kernel

Steps to Reproduce

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(Optional for Linux users) Output of /opt/rocm/bin/rocminfo --support

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Additional Information

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