feat: 引入可切换星历模型并扩展天象观测链路

- 新增半解析、旧模型、自定义与多源堆叠星历实例，提供 Context、Instance、SPK 读取及状态与视位置计算
- 统一太阳、月球和行星实例接口，扩展黄经穿越、留、相位、最近角距、偕日可见、任意高度升落、轨道节点及凌日等天象查询
- 完善日月食、月掩与凌日的月缘剖面、有限盘面接触、站心修正、局地可见性、全球路径和地图输出
- 新增 SVG、GeoJSON、KML 天象输出及凌日、月掩和月缘地形相关缓存与几何求解
- 新增恒星星表导入与查询，支持 CSV、Hipparcos、BSC5、Stellarium 等格式及名称、交叉标识、锥面检索和星等过滤
- 补充 IAU 2006、地球定向、折射消光、大气观测、轨道传播及半解析行星/月球数据支持
- 将默认未来民用时标切换为 TimeScaleLeapHour，更新 2027–2400 农历速查表、中文日期解析和时区边界处理
- 增加事件基线、跨模型回归、几何边界、月缘地形和输出契约测试，完善中英文手册、示例资源、NOTICE 与忽略规则

basic/solar_eclipse_rise_set_arc.go

@@ -3,6 +3,8 @@ package basic
 import (
 	"math"
 	"sort"
+
+	"b612.me/astro/internal/geodata"
 )
 
 const (
@@ -261,7 +263,12 @@ func (solver solarEclipseSolver) closeSolarEclipseRiseSetArcFolds(
 			if len(segment) < 2 {
 				continue
 			}
-			for _, pointIndex := range []int{0, len(segment) - 1} {
+			for _, last := range []bool{false, true} {
+				// 加密首边会改变段长，末点下标必须取当前段。
+				pointIndex := 0
+				if last {
+					pointIndex = len(curve.Segments[segmentIndex]) - 1
+				}
 				endpoint := curve.Segments[segmentIndex][pointIndex]
 				if solarEclipseRiseSetArcEndpointShared(curves, curveIndex, segmentIndex, pointIndex) {
 					continue
@@ -286,7 +293,9 @@ func (solver solarEclipseSolver) closeSolarEclipseRiseSetArcFolds(
 					solarEclipsePathDistanceKM(fold, endpoint) > maximumFoldDistance {
 					continue
 				}
-				curve.Segments[segmentIndex][pointIndex] = fold
+				curve.Segments[segmentIndex] = solver.replaceRiseSetArcEndpoint(
+					curve.Segments[segmentIndex], last, fold, curve.Phase, curve.Direction,
+				)
 				bestJunction := SolarEclipsePathPoint{}
 				bestMetric := math.Inf(1)
 				for _, junction := range junctions {
@@ -327,6 +336,30 @@ func (solver solarEclipseSolver) closeSolarEclipseRiseSetArcFolds(
 	}
 }
 
+// replaceRiseSetArcEndpoint 把段端点移到细化后的折点，新边照常加密而不留长弦。
+func (solver solarEclipseSolver) replaceRiseSetArcEndpoint(
+	segment []SolarEclipsePathPoint,
+	last bool,
+	fold SolarEclipsePathPoint,
+	phase RiseSetPhase,
+	direction RiseSetDirection,
+) []SolarEclipsePathPoint {
+	if len(segment) < 2 {
+		return segment
+	}
+	if !last {
+		edge := solver.appendRefinedRiseSetSegment(
+			[]SolarEclipsePathPoint{fold}, fold, segment[1], phase, direction, 0,
+		)
+		return append(edge, segment[2:]...)
+	}
+	neighbor := segment[len(segment)-2]
+	edge := solver.appendRefinedRiseSetSegment(
+		[]SolarEclipsePathPoint{neighbor}, neighbor, fold, phase, direction, 0,
+	)
+	return append(segment[:len(segment)-2:len(segment)-2], edge...)
+}
+
 func solarEclipseRiseSetArcEndpointShared(
 	curves []SolarEclipseRiseSetCurve,
 	curveIndex, segmentIndex, pointIndex int,
@@ -724,7 +757,7 @@ func (solver solarEclipseSolver) correctRiseSetArc(
 		for index := range coordinates {
 			coordinates[index] += delta[index]
 		}
-		coordinates[0] = normalizeLongitude(coordinates[0])
+		coordinates[0] = geodata.NormalizeLongitude(coordinates[0])
 		if coordinates[1] <= -89.999999 || coordinates[1] >= 89.999999 {
 			return solarEclipseRiseSetArcState{}, iteration, false
 		}
@@ -744,7 +777,7 @@ func (solver solarEclipseSolver) validRiseSetArcState(
 	iterations int,
 ) (solarEclipseRiseSetArcState, int, bool) {
 	jde := referenceJDE + coordinates[2]/solarEclipseRiseSetArcTimeScale
-	longitude, latitude := normalizeLongitude(coordinates[0]), coordinates[1]
+	longitude, latitude := geodata.NormalizeLongitude(coordinates[0]), coordinates[1]
 	evaluation := solver.magnitudeEvaluationAt(jde)
 	state := evaluation.center.stateAt(longitude*rad, latitude*rad, 0)
 	tangent, ok := solarEclipseMagnitudeArcTangent(jacobian)
@@ -766,7 +799,7 @@ func (solver solarEclipseSolver) riseSetArcJacobian(
 	referenceJDE float64,
 ) ([2]float64, [2][3]float64, bool) {
 	jde := referenceJDE + coordinates[2]/solarEclipseRiseSetArcTimeScale
-	longitude, latitude := normalizeLongitude(coordinates[0]), coordinates[1]
+	longitude, latitude := geodata.NormalizeLongitude(coordinates[0]), coordinates[1]
 	evaluation := solver.magnitudeEvaluationAt(jde)
 	residual, ok := solarEclipseRiseSetArcResidualAt(evaluation, longitude, latitude, greatest)
 	if !ok {
@@ -933,7 +966,7 @@ func (solver solarEclipseSolver) riseSetArcTransition(
 	if firstAltitudeDerivative*secondAltitudeDerivative <= 0 {
 		if point, ok := solver.refineRiseSetDirectionJunction(
 			(first.point.JDE+second.point.JDE)/2,
-			normalizeLongitude(first.point.Longitude+math.Remainder(second.point.Longitude-first.point.Longitude, 360)/2),
+			geodata.NormalizeLongitude(first.point.Longitude+math.Remainder(second.point.Longitude-first.point.Longitude, 360)/2),
 			(first.point.Latitude+second.point.Latitude)/2,
 			greatest,
 		); ok {
@@ -1023,7 +1056,7 @@ func solarEclipseRiseSetArcPointAtTime(
 	fraction := (jd - before.JDE) / (after.JDE - before.JDE)
 	return SolarEclipsePathPoint{
 		JDE: jd,
-		Longitude: normalizeLongitude(
+		Longitude: geodata.NormalizeLongitude(
 			before.Longitude + fraction*math.Remainder(after.Longitude-before.Longitude, 360),
 		),
 		Latitude: before.Latitude + fraction*(after.Latitude-before.Latitude),