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

basic/moon_geocentric_apparent_external_test.go

@@ -34,7 +34,7 @@ func TestMoonGeocentricApparentCoordinatesMatchHorizonsBaseline(t *testing.T) {
 		if err != nil {
 			t.Fatalf("parse sample time %q: %v", sample.InputUTC, err)
 		}
-		jd := TD2UT(Date2JDE(date.UTC()), true)
+		jd := UTC2TT(Date2JD(date.UTC()))
 		prefix := "moon." + sample.InputUTC
 
 		assertPlanetApparentAngleClose(t, prefix+".RightAscension", HMoonGeocentricApparentRa(jd), sample.RightAscension, 0.001)
@@ -54,7 +54,7 @@ func TestMoonGeocentricTrueCoordinatesFollowDefinition(t *testing.T) {
 	}
 
 	for _, sample := range samples {
-		jd := TD2UT(Date2JDE(sample.UTC()), true)
+		jd := UTC2TT(Date2JD(sample.UTC()))
 		wantRA, wantDec := LoBoToRaDec(jd, HMoonTrueLo(jd), HMoonTrueBo(jd))
 		gotRA, gotDec := HMoonGeocentricTrueRaDec(jd)