Rename CLI command from wmk to winml

[timenick]

Summary

Rename the CLI entry point from wmk to winml across the entire repository.

Scope

• Entry point: pyproject.toml scripts.wmk → scripts.winml
• CLI core: cli.py prog_name and docstrings
• Commands: docstring/usage examples in all 11 command files (export, build, config, analyze, quantize, optimize, compile, inspect, sys, eval, perf)
• Source code: error messages, validator hints, cache docstrings, temp dir prefix (wmk_ → winml_)
• venv-wmk → venv-winml (QAIRT SDK virtual environment name, 4 places)
• Tests: 11 test files referencing wmk
• Docs & scripts: README.md, e2e_eval scripts, wmk_metric_key → winml_metric_key in JSON config (22 places)
• Cleanup: delete src/winml_modelkit.egg-info/

Total: ~249 occurrences across 40 files. No backward-compatible alias — direct removal.