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

basic/moon_max_declination_perf_test.go

@@ -0,0 +1,91 @@
+package basic
+
+import (
+	"math"
+	"testing"
+)
+
+// 本文件用改动前的“七个候选全精修”实现做差分对照与 A/B 基准。
+
+func moonMaximumDeclinationReferenceSearch(jd float64, coeffs moonMaxDeclinationCoefficients, direction int, includeCurrent bool) DeclinationEvent {
+	if !finite(jd) {
+		return DeclinationEvent{}
+	}
+	cfg := moonMaximumDeclinationSearchConfig(coeffs)
+	centerK := moonMaximumDeclinationOffset(jd, coeffs)
+	found := false
+	bestDistance := math.Inf(1)
+	var best DeclinationEvent
+	for offset := -moonMaxDeclinationSearchSpan; offset <= moonMaxDeclinationSearchSpan; offset++ {
+		event := moonMaximumDeclinationEvent(centerK+offset, coeffs, cfg)
+		delta := event.JDE - jd
+		if !moonMaximumDeclinationMatchesDirection(delta, direction, includeCurrent) {
+			continue
+		}
+		distance := math.Abs(delta)
+		if !found || distance < bestDistance || (distance == bestDistance && moonMaximumDeclinationEarlier(event, best)) {
+			best = event
+			bestDistance = distance
+			found = true
+		}
+	}
+	return best
+}
+
+func moonMaximumDeclinationReferenceClosest(jd float64, coeffs moonMaxDeclinationCoefficients) DeclinationEvent {
+	if !finite(jd) {
+		return DeclinationEvent{}
+	}
+	last := moonMaximumDeclinationReferenceSearch(jd, coeffs, -1, true)
+	next := moonMaximumDeclinationReferenceSearch(jd, coeffs, 1, false)
+	lastDistance := math.Abs(jd - last.JDE)
+	nextDistance := math.Abs(next.JDE - jd)
+	if lastDistance <= nextDistance {
+		return last
+	}
+	return next
+}
+
+func TestMoonMaximumDeclinationPruningMatchesFullSearch(t *testing.T) {
+	for _, coeffs := range []moonMaxDeclinationCoefficients{moonMaxDeclinationNorthCoefficients, moonMaxDeclinationSouthCoefficients} {
+		for jd := JDECalc(2024, 1, 1); jd <= JDECalc(2025, 6, 1); jd += 2.5 {
+			for _, direction := range []struct {
+				name           string
+				dir            int
+				includeCurrent bool
+				fn             func(float64) DeclinationEvent
+			}{
+				{"Last", -1, true, func(v float64) DeclinationEvent {
+					return moonMaximumDeclinationSearch(v, coeffs, -1, true)
+				}},
+				{"Next", 1, false, func(v float64) DeclinationEvent {
+					return moonMaximumDeclinationSearch(v, coeffs, 1, false)
+				}},
+			} {
+				want := moonMaximumDeclinationReferenceSearch(jd, coeffs, direction.dir, direction.includeCurrent)
+				got := direction.fn(jd)
+				if got != want {
+					t.Fatalf("k=%v %s(%v) = %+v, want %+v", coeffs.sign, direction.name, jd, got, want)
+				}
+			}
+			wantClosest := moonMaximumDeclinationReferenceClosest(jd, coeffs)
+			if got := moonClosestMaximumDeclination(jd, coeffs); got != wantClosest {
+				t.Fatalf("k=%v Closest(%v) = %+v, want %+v", coeffs.sign, jd, got, wantClosest)
+			}
+		}
+	}
+}
+
+func BenchmarkMoonMaximumDeclinationFullSearchReference(b *testing.B) {
+	jd := JDECalc(2025, 3, 1)
+	b.Run("Next", func(b *testing.B) {
+		for i := 0; i < b.N; i++ {
+			_ = moonMaximumDeclinationReferenceSearch(jd, moonMaxDeclinationNorthCoefficients, 1, false)
+		}
+	})
+	b.Run("Closest", func(b *testing.B) {
+		for i := 0; i < b.N; i++ {
+			_ = moonMaximumDeclinationReferenceClosest(jd, moonMaxDeclinationNorthCoefficients)
+		}
+	})
+}