Adopt MIT license and prepare v1.0.1

[RandyNorthrup]

Summary

• replace proprietary repository license with standard MIT License
• bind generated and verified SPDX package metadata to MIT
• add archive assertions for MIT license and SBOM fields
• redesign README with accessible badges, clear workflow, quick start, compatibility, security, and honest release-license scope
• update install guidance and changelog
• bump package and skill version to 1.0.1 while keeping compatible payload schema 1.0.0

Verification

• python scripts/certify.py
• 65 tests passed; one Windows symlink test skipped because required OS privilege was unavailable
• Ruff, mypy, schema, deterministic packaging, extracted release verification, SPDX validation, and 81.59% coverage passed

Repository metadata

GitHub topics were updated separately through repository settings and are already live.