fix: 兼容 TinyGo wasm 编译行星星历初始化

- 将 planetViews 从包级初始化改为 sync.Once 懒加载，避免 TinyGo interp 在编译期处理大型 float64 表切片索引时触发 unsupported fcmp
- 将行星视图构建失败改为内部返回 error，并由兼容层统一 panic
- 补充无效行星数据切片边界测试

planet/planet.go

@@ -25,7 +25,7 @@ func WherePlanetN(xt, zn int, jd float64, n int) float64 {
 	t := (jd - 2451545) / 36525.0000
 	t /= 10 // 转为儒略千年数
 
-	body := planetViews[xt]
+	body := planetViews()[xt]
 	coord := body.coords[zn]
 	baseOrderTerms := len(coord.orders[0])
 

planet/planet_test.go

@@ -25,8 +25,9 @@ func TestWherePlanetNFullMatchesDefault(t *testing.T) {
 }
 
 func TestPlanetViewsMatchRawCuts(t *testing.T) {
+	views := planetViews()
 	for bodyIndex, raw := range planetRawData {
-		view := planetViews[bodyIndex]
+		view := views[bodyIndex]
 		if math.Float64bits(view.scale) != math.Float64bits(raw[0]) {
 			t.Fatalf("body=%d scale mismatch", bodyIndex)
 		}
@@ -42,3 +43,15 @@ func TestPlanetViewsMatchRawCuts(t *testing.T) {
 		}
 	}
 }
+
+func TestBuildPlanetViewsRejectsInvalidCuts(t *testing.T) {
+	_, err := buildPlanetViews([][]float64{{
+		10000000000,
+		20, 21, 20, 20, 20, 20, 20,
+		20, 20, 20, 20, 20, 20,
+		20, 20, 20, 20, 20, 20,
+	}})
+	if err == nil {
+		t.Fatal("expected invalid cut error")
+	}
+}

planet/view.go

@@ -1,6 +1,9 @@
 package planet
 
-import "fmt"
+import (
+	"fmt"
+	"sync"
+)
 
 type coordSeriesView struct {
 	orders [6][]float64
@@ -11,13 +14,27 @@ type planetView struct {
 	coords [3]coordSeriesView
 }
 
-var planetViews = buildPlanetViews(planetRawData)
+var (
+	planetViewsOnce  sync.Once
+	planetViewsCache []planetView
+	planetViewsErr   error
+)
 
-func buildPlanetViews(rawData [][]float64) []planetView {
+func planetViews() []planetView {
+	planetViewsOnce.Do(func() {
+		planetViewsCache, planetViewsErr = buildPlanetViews(planetRawData)
+	})
+	if planetViewsErr != nil {
+		panic(planetViewsErr)
+	}
+	return planetViewsCache
+}
+
+func buildPlanetViews(rawData [][]float64) ([]planetView, error) {
 	views := make([]planetView, len(rawData))
 	for bodyIndex, raw := range rawData {
 		if len(raw) < 20 {
-			panic(fmt.Sprintf("planet raw data %d too short: %d", bodyIndex, len(raw)))
+			return nil, fmt.Errorf("planet raw data %d too short: %d", bodyIndex, len(raw))
 		}
 		view := planetView{scale: raw[0]}
 		for zn := 0; zn < 3; zn++ {
@@ -26,12 +43,12 @@ func buildPlanetViews(rawData [][]float64) []planetView {
 				start := int(raw[pn+order])
 				end := int(raw[pn+order+1])
 				if start < 0 || end < start || end > len(raw) {
-					panic(fmt.Sprintf("planet raw data %d coord %d order %d invalid cut: %d..%d (len=%d)", bodyIndex, zn, order, start, end, len(raw)))
+					return nil, fmt.Errorf("planet raw data %d coord %d order %d invalid cut: %d..%d (len=%d)", bodyIndex, zn, order, start, end, len(raw))
 				}
 				view.coords[zn].orders[order] = raw[start:end]
 			}
 		}
 		views[bodyIndex] = view
 	}
-	return views
+	return views, nil
 }