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/julian_zone_test.go

@@ -0,0 +1,28 @@
+package basic
+
+import (
+	"testing"
+	"time"
+)
+
+func TestLocalJulianDayAcrossDST(t *testing.T) {
+	for _, name := range []string{"America/New_York", "Australia/Lord_Howe"} {
+		loc, err := time.LoadLocation(name)
+		if err != nil {
+			t.Fatal(err)
+		}
+		for _, md := range [][2]int{{3, 8}, {11, 1}, {4, 5}, {10, 4}} {
+			for _, hour := range []int{0, 3, 12, 23} {
+				want := time.Date(2026, time.Month(md[0]), md[1], hour, 17, 23, 125000000, loc)
+				got := JD2DateByZone(Date2JD(want), loc, true)
+				if delta := got.Sub(want); delta < -100*time.Microsecond || delta > 100*time.Microsecond {
+					t.Errorf("local %s: got %s, delta=%s", want, got, delta)
+				}
+				got = JD2DateByZone(Date2JD(want.UTC()), loc, false)
+				if delta := got.Sub(want); delta < -100*time.Microsecond || delta > 100*time.Microsecond {
+					t.Errorf("UTC %s: got %s, delta=%s", want, got, delta)
+				}
+			}
+		}
+	}
+}