feat(optim): show custom operator domains

[xieofxie]

Summary

• preserve ONNX node domains in optimization analysis results
• qualify non-default-domain operators in --check-optim output, such as com.microsoft::Gelu
• include custom domains in structured optimization-output data while keeping default ONNX operator output unchanged

Validation

• uv run pytest tests/unit/optim/test_analysis.py tests/unit/commands/test_optimize_cli.py tests/unit/analyze/test_optim_output.py
• uv run ruff check --fix src/winml/modelkit/optim/analysis.py src/winml/modelkit/analyze/optim_output.py tests/unit/optim/test_analysis.py tests/unit/commands/test_optimize_cli.py tests/unit/analyze/test_optim_output.py

[Qiong Wu (qiowu) (DingmaomaoBJTU)]

Reviewed the domain propagation through graph collection, diff reporting, CLI rendering, structured optimization output, and produced-operator support. The implementation is backward compatible for default-domain ONNX nodes and all CI checks pass. No blocking findings.

[Qiong Wu (qiowu) (DingmaomaoBJTU)]

LGTM. Re-reviewed the latest head. The added test locks down backward-compatible serialization for the explicit ai.onnx domain, custom-domain propagation remains correct, and all CI checks pass.