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/sun_physical_test.go

@@ -35,7 +35,7 @@ func TestSunPhysicalMatchesHorizonsBaseline(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()))
 		got := SunPhysical(jd)
 
 		pDiff := angleDiffAbs(got.P, sample.P)
@@ -60,7 +60,7 @@ func TestSunPhysicalMatchesHorizonsBaseline(t *testing.T) {
 }
 
 func TestSunPhysicalNFullMatchesDefault(t *testing.T) {
-	jd := TD2UT(Date2JDE(time.Date(2026, 4, 28, 9, 30, 45, 0, time.UTC)), true)
+	jd := UTC2TT(Date2JD(time.Date(2026, 4, 28, 9, 30, 45, 0, time.UTC)))
 
 	got := SunPhysical(jd)
 	gotN := SunPhysicalN(jd, -1)
@@ -81,7 +81,7 @@ func TestSunPhysicalSampleSweepFiniteAndInRange(t *testing.T) {
 	}
 
 	for _, date := range dates {
-		jd := TD2UT(Date2JDE(date.UTC()), true)
+		jd := UTC2TT(Date2JD(date.UTC()))
 		got := SunPhysical(jd)
 		prefix := date.Format(time.RFC3339)