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

eclipse/svg/lunar_model.go

@@ -4,6 +4,7 @@ import (
 	"math"
 	"time"
 
+	"b612.me/astro"
 	"b612.me/astro/basic"
 	eclipsecore "b612.me/astro/eclipse"
 )
@@ -21,8 +22,11 @@ const (
 	LunarEclipseTotal     = eclipsecore.LunarEclipseTotal
 )
 
-func lunarEclipseInfoFromBasic(result basic.LunarEclipseResult, location *time.Location) LunarEclipseInfo {
-	return LunarEclipseInfo{
+func lunarEclipseInfoFromBasic(
+	result basic.LunarEclipseResult,
+	location *time.Location,
+) LunarEclipseInfo {
+	info := LunarEclipseInfo{
 		Type:               mapBasicLunarEclipseType(result.Type),
 		PenumbralMagnitude: result.PenumbralMagnitude,
 		UmbralMagnitude:    result.Magnitude,
@@ -38,6 +42,16 @@ func lunarEclipseInfoFromBasic(result basic.LunarEclipseResult, location *time.L
 		HasPartial:         result.HasPartial,
 		HasTotal:           result.HasTotal,
 	}
+	return info
+}
+
+// lunarEclipseDisplayInfo 给出写图用的时刻副本；几何必须用未换算的 UTC 时刻，
+// 否则把 UT1 读数当民用时刻会平移地平线、月下点与地心坐标块。
+func lunarEclipseDisplayInfo(info LunarEclipseInfo, scale astro.TimeScale) LunarEclipseInfo {
+	if scale == astro.TimeScaleUT1 {
+		return eclipsecore.LunarEclipseInfoInUT1(info)
+	}
+	return info
 }
 
 func lunarEclipseContactPointsFromBasic(
@@ -128,13 +142,13 @@ func ttJDEToTime(ttJDE float64, location *time.Location) time.Time {
 	if ttJDE == 0 {
 		return time.Time{}
 	}
-	utcJDE := basic.TD2UT(ttJDE, false)
-	return basic.JDE2DateByZone(utcJDE, location, false)
+	utcJD := basic.TT2UTC(ttJDE)
+	return basic.JD2DateByZone(utcJD, location, false)
 }
 
 func timeToTTJDE(date time.Time) float64 {
-	utcJDE := basic.Date2JDE(date.UTC())
-	return basic.TD2UT(utcJDE, true)
+	utcJD := basic.Date2JD(date.UTC())
+	return basic.UTC2TT(utcJD)
 }
 
 func normalizeDegree360(angle float64) float64 {