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_shadow.go

@@ -1,6 +1,8 @@
 package basic
 
-import "math"
+import (
+	"math"
+)
 
 // SolarEclipseShadowKind 阴影类型 / shadow kind.
 type SolarEclipseShadowKind int
@@ -125,6 +127,8 @@ func (instant SolarEclipseShadowInstant) Empty() bool {
 
 // SolarEclipseShadowSolver 可复用的单时刻求解器；非并发安全，宿主每条 lane 各持一个 / reusable solver, one per lane.
 type SolarEclipseShadowSolver struct {
+	inst *Instance
+
 	options SolarEclipseShadowSolverOptions
 
 	anchorSet    bool
@@ -132,8 +136,8 @@ type SolarEclipseShadowSolver struct {
 	anchorSolver solarEclipseSolver
 }
 
-// NewSolarEclipseShadowSolver 构造单时刻求解器 / builds a single-instant solver.
-func NewSolarEclipseShadowSolver(options SolarEclipseShadowSolverOptions) *SolarEclipseShadowSolver {
+// NewSolarEclipseShadowSolverWithInstance 用指定星历实例求值；inst 为 nil 时用进程当前模型 / evaluation with an explicit instance; nil uses the process model.
+func NewSolarEclipseShadowSolverWithInstance(options SolarEclipseShadowSolverOptions, inst *Instance) *SolarEclipseShadowSolver {
 	options.Model = normalizeSolarEclipseRadiusModel(options.Model)
 	options.SunRadiusModel = normalizeSolarEclipseSunRadiusModel(options.SunRadiusModel)
 	if options.BoundaryPoints <= 0 {
@@ -156,7 +160,7 @@ func NewSolarEclipseShadowSolver(options SolarEclipseShadowSolverOptions) *Solar
 	if options.TargetSpacingKM < 0 {
 		options.TargetSpacingKM = 0
 	}
-	return &SolarEclipseShadowSolver{options: options}
+	return &SolarEclipseShadowSolver{inst: inst, options: options}
 }
 
 // ShadowAtJDE 给定 TT 时刻的阴影足迹；不在地球上时返回 (零值, false) / footprint at one TT instant.
@@ -210,13 +214,13 @@ func (solver *SolarEclipseShadowSolver) solverFor(jdeTT float64) solarEclipseSol
 	if solver.anchorSet && math.Abs(jdeTT-solver.anchorJDE) <= solarEclipseShadowAnchorHalfWindowDays {
 		return solver.anchorSolver
 	}
-	anchor := CalcMoonSHByJDE(jdeTT, 0)
+	anchor := solarEclipseAnchorNewMoon(jdeTT, solver.inst)
 	solver.anchorSet = true
 	solver.anchorJDE = anchor
 	solver.anchorSolver = newSolarEclipseSolverWithOptions(anchor, SolarEclipseOptions{
 		RadiusModel:    solver.options.Model,
 		SunRadiusModel: solver.options.SunRadiusModel,
-	})
+	}, solver.inst)
 	return solver.anchorSolver
 }
 
@@ -228,7 +232,7 @@ func (solver *SolarEclipseShadowSolver) besselGeometryAt(
 	if solver.options.DeltaTSeconds <= 0 {
 		return inner.besselGeometryAt(jdeTT)
 	}
-	sunEquatorial, moonEquatorial := solarEclipseSunMoonEquatorial(jdeTT)
+	sunEquatorial, moonEquatorial := solarEclipseSunMoonEquatorial(jdeTT, solver.inst)
 	axis := solarEclipseBesselAxisFromEquatorialWithDeltaT(
 		jdeTT, sunEquatorial, moonEquatorial, deltaTSeconds,
 	)
@@ -311,7 +315,7 @@ func (solver *SolarEclipseShadowSolver) StationStateAtJDE(
 	heightKM := heightMeters / 1000
 	state := localSolarEclipseStateAtWithDeltaT(
 		jdeTT, deltaT, lonDeg*rad, latDeg*rad, heightKM,
-		solarEclipseModelParams(solver.options.Model, solver.options.SunRadiusModel),
+		solarEclipseModelParams(solver.options.Model, solver.options.SunRadiusModel), solver.inst,
 	)
 	contact := state.movingDiskContactState()
 	central := contact.internalContactGap() <= 0
@@ -361,17 +365,19 @@ func SolarEclipseStationStateAtJDE(
 
 func localSolarEclipseStateAtWithDeltaT(
 	jdTT, deltaTSeconds, lonRad, latRad, heightKM float64,
-	params solarEclipseModelParameters,
-) localSolarEclipseState {
-	context := newLocalSolarEclipseStateContextWithDeltaT(jdTT, deltaTSeconds, params)
+	params solarEclipseModelParameters, instances ...*Instance) localSolarEclipseState {
+	inst := instanceValue(instances)
+
+	context := newLocalSolarEclipseStateContextWithDeltaT(jdTT, deltaTSeconds, params, inst)
 	return context.stateAt(lonRad, latRad, heightKM)
 }
 
 func newLocalSolarEclipseStateContextWithDeltaT(
 	jdTT, deltaTSeconds float64,
-	params solarEclipseModelParameters,
-) localSolarEclipseStateContext {
-	sunEquatorial, moonEquatorial := solarEclipseSunMoonEquatorial(jdTT)
+	params solarEclipseModelParameters, instances ...*Instance) localSolarEclipseStateContext {
+	inst := instanceValue(instances)
+
+	sunEquatorial, moonEquatorial := solarEclipseSunMoonEquatorial(jdTT, inst)
 	utJDE := jdTT - deltaTSeconds/86400
 	return localSolarEclipseStateContext{
 		sunXYZ:  solarEclipseLLRToXYZ(sunEquatorial[0], sunEquatorial[1], sunEquatorial[2]),