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

moon/geocentric_apparent_test.go

@@ -35,7 +35,7 @@ func TestGeocentricApparentRaDecDiffersFromTopocentricAtSite(t *testing.T) {
 func TestTrueRaDecUsesBasicGeocentricTrue(t *testing.T) {
 	date := time.Date(2026, 1, 1, 6, 0, 0, 0, time.UTC)
 
-	wantRA, wantDec := basic.HMoonGeocentricTrueRaDec(basic.TD2UT(basic.Date2JDE(date.UTC()), true))
+	wantRA, wantDec := basic.HMoonGeocentricTrueRaDec(basic.UTC2TT(basic.Date2JD(date.UTC())))
 	gotRA, gotDec := TrueRaDec(date)
 	if math.Abs(gotRA-wantRA) > 1e-12 || math.Abs(gotDec-wantDec) > 1e-12 {
 		t.Fatalf("TrueRaDec mismatch: got (%.15f, %.15f) want (%.15f, %.15f)", gotRA, gotDec, wantRA, wantDec)