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_state_test.go

@@ -0,0 +1,17 @@
+package basic
+
+import "testing"
+
+// TestMoonStateMatchesHMoonHeight 固定 MoonState 与 HMoonHeight 逐位同口径。
+func TestMoonStateMatchesHMoonHeight(t *testing.T) {
+	for _, jd := range []float64{2462502.5, 2416745.5, 2469807.75, 2378496.25} {
+		state := MoonStateAt(jd)
+		for lon := -180.0; lon < 180; lon += 23.5 {
+			for lat := -89.5; lat <= 89.5; lat += 7.5 {
+				if got, want := state.HMoonHeight(lon, lat), HMoonHeight(jd, lon, lat, 0); got != want {
+					t.Fatalf("jd=%v lon=%v lat=%v got %v want %v", jd, lon, lat, got, want)
+				}
+			}
+		}
+	}
+}