Fix Windows release archive validation

[openai0229]

Summary

• compare release archive members structurally inside Python
• add native Windows packaging regression coverage
• advance the CLI and bundled Skill to 0.2.1 after the immutable 0.2.0 release attempt failed before publication

Verification

• cargo test --locked --all-targets: 389 passed
• cargo clippy --locked --all-targets -- -D warnings
• package reproducibility and metadata checks
• development installer tests
• actionlint and shellcheck
• documentation, license, Action pin, and release policy checks
• local darwin-arm64 release package

Release impact

The failed 0.2.0 run did not upload CDN objects or create a GitHub Release. The immutable v0.2.0 tag remains unchanged; the corrected public release will be v0.2.1.

Closes #7