v0.3.0

Added

• add four-pillar (BaZi) Ganzhi API and solar-term boundaries (#5)

Fixed

• restore release-plz workflow (#6)

Added

• Four-pillar (四柱 / 八字 BaZi) stem-branch calculation, a faithful port of the
  TypeScript lunar-lite@0.2.8 getHeavenlyStemAndEarthlyBranchBySolarDate:
  • FourPillars (with yearly, monthly, daily, hourly) and the Rust-native
    constructors four_pillars_from_solar_date (default options) and
    four_pillars_from_solar_date_with_options.
  • TS-compatible get_heavenly_stem_and_earthly_branch_by_solar_date and
    ..._with_options, plus the HeavenlyStemAndEarthlyBranchDate type alias for
    FourPillars, mirroring the TypeScript reference names.
  • StemBranchOptions (default Exact/Exact) with YearDivide (Normal =
    lunar year, Exact = 立春 at date granularity) and MonthDivide (Normal =
    lunar-month 五虎遁, Exact = 12 Jie solar terms at exact second).
  • Day pillar via Julian-day arithmetic with 晚子时 (late 子) day rollover at
    time_index 12.
  • Supported range 1850-01-01 ..= 2150-12-31.
• Generated 12-Jie solar-term boundary table (src/generated/solar_terms.rs) from
  lunar-typescript@1.8.6, plus generate-solar-terms.mjs and
  generate-four-pillars-fixtures.mjs generators.
• LunarError::InvalidTimeIndex and LunarError::SolarTermOutOfRange variants.
• serde support for the new four-pillar types (behind the serde feature).
• Fixture-driven compatibility tests against lunar-lite@0.2.8 output.