feat: 完善日月食与月掩几何链路并扩展历法接口

- 新增日月食中心带、偏食带、阴影足迹、等时线、食分线及升落边界计算，支持极区与混合食拓扑
- 新增日食单时刻阴影求解器、站心状态查询、批量采样和 ΔT 覆盖接口
- 重构恒星与行星月掩路径，补充有限盘面接触、站心修正、掩带宽度、极区投影及升落边界
- 扩展 SVG 与 GeoJSON 输出，支持详细面板、全球/极区/地球投影、边界闭合、时间标记和拓扑签名
- 扩展日月食候选搜索、局地搜索、沙罗序列预计算与范围外推，补充系列锚点和成员一致性校验
- 补齐古历纪年、儒略历独有闰日、多公历候选、历法改革跨日及精确日期运算接口
- 优化 ΔT、章动、恒星时、月球地平线、事件根搜索和本地星历缓存，降低重复计算开销并提升边界稳定

jupiter/satellites_test.go

@@ -6,9 +6,12 @@ import (
 	"os"
 	"testing"
 	"time"
+
+	"b612.me/astro/basic"
 )
 
-const galileanHorizonsToleranceArcsec = 1.0
+// 基线是 UTC 瞬时地心赤道量的派生偏移，容差取实测最大残差（0.054″）的约三倍。
+const galileanHorizonsToleranceArcsec = 0.15
 
 type galileanHorizonsEquatorialRecord struct {
 	RA    float64 `json:"ra_deg"`
@@ -95,3 +98,22 @@ func selectGalileanSatellite(info GalileanSatellitesInfo, name string) GalileanS
 		panic("unknown satellite: " + name)
 	}
 }
+
+func TestGalileanSatellitesUseTTFrame(t *testing.T) {
+	dates := []time.Time{
+		time.Date(1973, 4, 15, 0, 0, 0, 0, time.UTC),
+		time.Date(1999, 1, 1, 2, 0, 0, 0, time.UTC),
+		time.Date(2026, 4, 2, 18, 0, 0, 0, time.UTC),
+	}
+	for _, date := range dates {
+		want := basic.JupiterGalileanSatelliteObservations(basic.TD2UT(basic.Date2JDE(date.UTC()), true))
+		got := Satellites(date)
+		positions := []GalileanSatellitePosition{got.Io, got.Europa, got.Ganymede, got.Callisto}
+		for i, position := range positions {
+			expected := galileanSatellitePositionFromBasic(want[i])
+			if position != expected {
+				t.Fatalf("date=%s satellite=%d TT frame mismatch: got %+v want %+v", date, i+1, position, expected)
+			}
+		}
+	}
+}