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

orbit/perf_bench_test.go

@@ -0,0 +1,59 @@
+package orbit
+
+import (
+	"testing"
+	"time"
+)
+
+var (
+	benchmarkParallacticSink float64
+	benchmarkPositionSink    EquatorialPosition
+)
+
+func benchmarkObservationInputs() (time.Time, Elements) {
+	return time.Date(2025, 11, 21, 20, 0, 0, 0, time.FixedZone("CST", 8*3600)), sampleObservationElements()
+}
+
+func BenchmarkParallacticAngle(b *testing.B) {
+	date, elements := benchmarkObservationInputs()
+	b.ReportAllocs()
+	b.ResetTimer()
+	sink := 0.0
+	for i := 0; i < b.N; i++ {
+		sink = ParallacticAngle(date, elements, shanghaiLon, shanghaiLat, shanghaiHeightMeters)
+	}
+	benchmarkParallacticSink = sink
+}
+
+func BenchmarkParallacticAngleLegacy(b *testing.B) {
+	date, elements := benchmarkObservationInputs()
+	b.ReportAllocs()
+	b.ResetTimer()
+	sink := 0.0
+	for i := 0; i < b.N; i++ {
+		sink = duplicatedSolveParallacticAngle(date, elements, shanghaiLon, shanghaiLat, shanghaiHeightMeters)
+	}
+	benchmarkParallacticSink = sink
+}
+
+func BenchmarkApparentTopocentricEquatorial(b *testing.B) {
+	date, elements := benchmarkObservationInputs()
+	b.ReportAllocs()
+	b.ResetTimer()
+	sink := EquatorialPosition{}
+	for i := 0; i < b.N; i++ {
+		sink = ApparentTopocentricEquatorial(date, elements, shanghaiLon, shanghaiLat, shanghaiHeightMeters)
+	}
+	benchmarkPositionSink = sink
+}
+
+func BenchmarkHourAngle(b *testing.B) {
+	date, elements := benchmarkObservationInputs()
+	b.ReportAllocs()
+	b.ResetTimer()
+	sink := 0.0
+	for i := 0; i < b.N; i++ {
+		sink = HourAngle(date, elements, shanghaiLon, shanghaiLat, shanghaiHeightMeters)
+	}
+	benchmarkParallacticSink = sink
+}