feat: 完善时标与天象几何计算并扩展输出接口

- 新增时标、ΔT 模型、质心时间与 UT1 支持
- 改进日月食、月掩、行星事件及路径边界计算
- 完善恒星三维自行与动态距离传播
- 扩展 SVG、GeoJSON、KML 输出与底层距离换算工具
- 整理中英文手册、示例资源及回归测试

star/parallactic.go

@@ -13,8 +13,8 @@ import (
 // ra/dec are apparent equatorial coordinates in degrees; lon/lat are east-positive and north-positive.
 // Returns the signed parallactic angle in degrees.
 func ParallacticAngle(date time.Time, ra, dec, lon, lat float64) float64 {
-	jde := basic.Date2JDE(date)
+	localJD := basic.Date2JD(date)
 	_, loc := date.Zone()
 	timezone := float64(loc) / 3600.0
-	return basic.StarParallacticAngle(jde, ra, dec, lon, lat, timezone)
+	return basic.StarParallacticAngle(localJD, ra, dec, lon, lat, timezone)
 }