# Changelog — QP-CAL-001

All notable changes to this paper specification are documented in this file.
The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).

## [1.0.0] - 2026-10-01

### Added
- Initial stable scholarly publication of the Quizzman Lunisolar Calendar System formal specification.
- Formalization of the continuous Julian Day conversion invariant (`utcDateTimeToJulianDate`).
- Full mathematical derivation and 129-term Meeus-abridged VSOP87 planetary reduction for solar ecliptic longitude.
- Canonical UTC solar term transition resolver (`getSolarTermTransitionsForYear`) eliminating civil boundary truncation defects.
- True Solar Time calculation engine integrating Meeus Chapter 28 Equation of Time and geographical meridian correction.
- Midnight date rollover propagation model (`effectiveLocalDateTime`, `effectiveJdn`) across Four Pillars and astrological modules.
- Strict lunisolar month assignment and "no major solar term" leap month determination rule.
- Sexagenary cycle (Can Chi) closed-form congruence equations for day, hour, month, and year pillars, including Dạ Tý / Chính Tý conventions.
- Complete algorithmic definitions for Thập Nhị Trực (12 Day Officers) and Nhị Thập Bát Tú (28 Mansions) anchored to epoch JDN 2449719.
- Exhaustive timeline of Vietnam's 8 historical civil time periods from pre-1906 to post-1975 reunification.
- In-depth documentation and formal resolution of the 9 core audit issues (A01 through A09).
- Machine-verifiable benchmark test suite containing 15 multi-domain test vectors in `artifacts/test-vectors.json`.
- Reproducibility manifest linking to `@quizzman/qm-calendar` v1.2.0.