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/solar_eclipse_test.go

@@ -119,6 +119,75 @@ func TestSolarEclipseAgainstNASABaseline(t *testing.T) {
 	}
 }
 
+func TestSolarEclipseBesselGeometryCacheSeparatesExactAndCandidate(t *testing.T) {
+	seed := JDECalc(2024, 4, 8)
+	solver := newSolarEclipseSolver(CalcMoonSHByJDE(seed, 0), SolarEclipseModelNASABulletinSplitK)
+	tt := solver.newMoonJDE + 0.125
+	exactMoon, exactAxis, exactSun := solver.besselGeometryAt(tt)
+	exactMoonAgain, exactAxisAgain, exactSunAgain := solver.besselGeometryAt(tt)
+	if exactMoon != exactMoonAgain || exactAxis != exactAxisAgain || exactSun != exactSunAgain {
+		t.Fatal("exact Bessel cache changed the geometry on a repeated lookup")
+	}
+	if len(solver.besselGeometryCache) != 1 {
+		t.Fatalf("exact Bessel cache size=%d, want 1", len(solver.besselGeometryCache))
+	}
+
+	candidateSolver := solver.withLocalEphemeris()
+	candidateMoon, candidateAxis, candidateSun, ok := candidateSolver.besselGeometryCandidateAt(tt)
+	if !ok {
+		t.Fatal("candidate Bessel geometry unavailable inside local ephemeris")
+	}
+	candidateMoonAgain, candidateAxisAgain, candidateSunAgain, okAgain := candidateSolver.besselGeometryCandidateAt(tt)
+	if !okAgain || candidateMoon != candidateMoonAgain || candidateAxis != candidateAxisAgain || candidateSun != candidateSunAgain {
+		t.Fatal("candidate Bessel cache changed the geometry on a repeated lookup")
+	}
+	if len(solver.besselGeometryCache) != 1 {
+		t.Fatalf("exact Bessel cache size changed after candidate lookup=%d", len(solver.besselGeometryCache))
+	}
+	if len(solver.besselCandidateCache) != 1 {
+		t.Fatalf("candidate Bessel cache size=%d, want 1", len(solver.besselCandidateCache))
+	}
+}
+
+func TestSolarEclipseBesselGeometryCacheIsBounded(t *testing.T) {
+	cache := make(map[uint64]solarEclipseBesselGeometryCacheEntry)
+	entry := solarEclipseBesselGeometryCacheEntry{valid: true}
+	for index := 0; index < solarEclipseBesselGeometryCacheMaximumEntries+17; index++ {
+		storeSolarEclipseBesselGeometry(cache, uint64(index), entry)
+	}
+	if len(cache) > solarEclipseBesselGeometryCacheMaximumEntries {
+		t.Fatalf("Bessel cache size=%d, want <=%d", len(cache), solarEclipseBesselGeometryCacheMaximumEntries)
+	}
+	if _, ok := cache[uint64(solarEclipseBesselGeometryCacheMaximumEntries+16)]; !ok {
+		t.Fatal("latest Bessel cache entry was evicted")
+	}
+}
+
+func BenchmarkSolarEclipseBesselGeometryCache(b *testing.B) {
+	solver := newSolarEclipseSolver(
+		CalcMoonSHByJDE(JDECalc(2024, 4, 8), 0),
+		SolarEclipseModelNASABulletinSplitK,
+	)
+	tt := solver.newMoonJDE + 0.125
+	// Prime one exact entry so the benchmark measures the repeated lookup
+	// path used by contact and topology refinements.
+	solver.besselGeometryAt(tt)
+	b.ReportAllocs()
+	b.ResetTimer()
+	for index := 0; index < b.N; index++ {
+		solver.besselGeometryAt(tt)
+	}
+}
+
+func BenchmarkSolarEclipseRepresentativePath(b *testing.B) {
+	seed := JDECalc(2024, 4, 8)
+	options := SolarEclipsePathOptions{StepDays: 5.0 / 1440.0, TargetSpacingKM: 200}
+	b.ReportAllocs()
+	for index := 0; index < b.N; index++ {
+		SolarEclipseCentralPath(seed, options)
+	}
+}
+
 func TestSolarEclipseDefaultUsesNASABulletinSplitK(t *testing.T) {
 	jde := JDECalc(2024, 4, 8)
 	defaultResult := SolarEclipse(jde)
@@ -174,6 +243,17 @@ func TestSolarEclipseNoEvent(t *testing.T) {
 	}
 }
 
+func BenchmarkSolarEclipseGlobal(b *testing.B) {
+	seed := JDECalc(2010, 1, 15)
+	b.ReportAllocs()
+	for iteration := 0; iteration < b.N; iteration++ {
+		result := SolarEclipse(seed)
+		if !result.HasCentral {
+			b.Fatal("expected a central eclipse")
+		}
+	}
+}
+
 func solarEclipseTTJDE(year int, month time.Month, day, hour, minute, second int) float64 {
 	return Date2JDE(time.Date(year, month, day, hour, minute, second, 0, time.UTC))
 }