Normalize W4A16 profiler scope grammar and report unique expert count

[roberteg16]

Summary

Two producer-side gaps that stop a W4A16 trace from becoming a bandwidth number.

1. Three spellings of one field. #1067 made the labels self-describing, but the group size is written three ways: bare g32 on the dense scopes, g=32 on the MoE ones, gs=/sk= on the AWQ GEMVs. Settle on key=value everywhere.

- wvsplitk_int4 1x43008x5376 g32 asym
+ wvsplitk_int4 1x43008x5376 g=32 asym

- awq_gemv_hip 5376x4096 gs=128 sk=2
+ awq_gemv_hip 5376x4096 g=128 split_k=2

hybrid_w4a16.py covers wvsplitk_int4, hybrid_dequant_w4a16 and hybrid_triton_w4a16 in one line — they share the _gz suffix.

2. The MoE scope carried no expert count. Weight slabs dominate that kernel's traffic and it loads one per block, but the count cannot be recovered downstream: a trace records expert_ids' length, not its contents, and several blocks can share an expert. So the block count is only an upper bound, and E/top_k a looser one. fused_moe_wvsplitk_int4 now emits the measured value:

fused_moe_wvsplitk_int4 4x1024x2048 E=256 top_k=8 g=128 sym experts=5

On the consumer side that is the difference between 5.23 MiB and 33.08 MiB of modelled traffic for a 32-block launch touching 5 distinct experts — 6.3x, in a byte model whose whole job is to be exact.

Test plan

End-to-end capture on gemma-4-31B-it-AWQ-4bit (decode, --profile --profile-record-shapes --profile-export-trace), with this branch installed:

• Labels come out in the new grammar: wvsplitk_int4 1x43008x5376 g=32 asym
• The roofline consumer reads them with zero warnings
• Per-shape bandwidth 188-204 GiB/s (81.8-88.8% of peak), matching the pre-change capture's 188.6-202.6 GiB/s within run-to-run noise

Also run:

MoE end-to-end on Qwen3.6-35B-A3B-W4A16-llmcompressor (256 experts, top_k=8, g=128 symmetric, decode with --profile --profile-record-shapes --profile-export-trace):

• The scope emits the measured count in a real run:
  fused_moe_wvsplitk_int4 1x1024x2048 E=256 top_k=8 g=128 sym experts=8
• experts=8 is exactly right: one token, top_k=8, so eight distinct experts
• The window attaches to the right op — the roofline reports
  [experts=8 measured] and (experts read = 8 of 256, measured), with zero warnings
• The same trace also exercises hybrid_triton_moe ... g=128 sym, one of the two labels Annotate W4A16 profiler scopes with group size and symmetry #1067 silently broke; it now parses

[roberteg16]

rocm-scripts counter part PR: https://gitenterprise.xilinx.com/FaaSApps/rocm-scripts/pull/878

[mgehre-amd]

Thanks!

[roberteg16]

Current pre-commit is not related to this PR. Merging