feat: 新增月掩与日月食地理绘图并提升观测计算精度

- 新增月掩恒星和行星：支持搜索、掩甚点、全球掩带及固定地点轨迹计算
- 支持恒星星表坐标转换、有限盘面行星接触事件和月掩 SVG 输出
- 新增日月食及月掩全球投影图、时间标记和 GeoJSON 地理数据接口
- 扩展日食中心线、南北界及偏食足迹采样，支持极区投影
- 修正站心时角、月出月落、月球视半径、折射和恒星自行计算
- 优化内外行星事件搜索、边界选择、极端输入处理和计算稳定性

basic/venus_event_regression_test.go

@@ -5,6 +5,7 @@ import (
 	"math"
 	"os"
 	"testing"
+	"time"
 )
 
 type venusEventBaselineSample struct {
@@ -47,7 +48,13 @@ func TestVenusEventBaselineRegression(t *testing.T) {
 				t.Fatalf("%s missing baseline event %s", sample.InputUTC, event.name)
 			}
 			want := math.Float64frombits(wantBits)
+			if math.IsNaN(want) || math.IsInf(want, 0) {
+				t.Fatalf("%s %s baseline is non-finite %v", sample.InputUTC, event.name, want)
+			}
 			got := event.fn(jd)
+			if math.IsNaN(got) || math.IsInf(got, 0) {
+				t.Fatalf("%s %s returned non-finite result %v", sample.InputUTC, event.name, got)
+			}
 			diff := math.Abs(got - want)
 			if diff > event.tolerance {
 				t.Fatalf("%s %s diff %.12f > tolerance %.12f", sample.InputUTC, event.name, diff, event.tolerance)
@@ -55,3 +62,16 @@ func TestVenusEventBaselineRegression(t *testing.T) {
 		}
 	}
 }
+
+func TestVenusConjunctionExtremeInputIsBounded(t *testing.T) {
+	started := time.Now()
+	for _, next := range []uint8{0, 1} {
+		got := venusConjunction(1e8, next)
+		if math.IsInf(got, 0) {
+			t.Fatalf("venusConjunction(1e8, %d) returned infinite result %v", next, got)
+		}
+	}
+	if elapsed := time.Since(started); elapsed > 2*time.Second {
+		t.Fatalf("venusConjunction extreme input took %s, want <= 2s", elapsed)
+	}
+}