2.0.0+upstream-2.1.19

What's Changed

• Full-package audit: C-layer data races, unified search semantics, API and CI hardening (2.0.0) by @heirloomlogic in #19
• Unify Moon ecliptic API, document upstream sync, build Apple platforms in CI by @heirloomlogic in #23

Full Changelog: 1.1.0+upstream-2.1.19...2.0.0+upstream-2.1.19