chore: close v0.2.0 release cycle

[yigitcan-ozturk]

Cleanup

• remove the one-time post-release verifier after its successful run
• mark every v0.2.0 release checklist item complete
• record the tagged release commit, successful main/release verification runs and published artifact digests
• record the retained GitHub Actions verification evidence

Verified before this cleanup

• GitHub Release rfqdiff v0.2.0 is public
• wheel and sdist are attached
• tagged release commit tests are green
• the actual published wheel was downloaded from the Release page, digest-checked, clean-installed and exercised through a representative CSV → JSON/XLSX comparison
• downstream supplier-scorecard and full Phase 2 procurement-pipeline compatibility are green

No product, scoring or API behavior changes.