fix: 修正行星事件边界与留点计算

- 统一 UT 事件时刻与 TT 查询时刻的边界判断
- 将外行星留点搜索锚定到对应冲日周期
- 修正水星、金星合日、留、大距事件选择
- 统一七大行星视位置计算辅助逻辑
- 增加公开 Last/Next 边界和 JPL/NAOJ 基线回归测试

basic/event_boundary.go

@@ -0,0 +1,76 @@
+package basic
+
+import "math"
+
+const exactEventTolerance = 2.0 / 86400.0
+
+func sameEventJD(a, b float64) bool {
+	return math.Abs(a-b) <= exactEventTolerance
+}
+
+func sameEventUTQueryTT(eventUT, queryTT float64) bool {
+	return math.Abs(eventUTQueryTTDelta(eventUT, queryTT)) <= exactEventTolerance
+}
+
+func closestEventUTToQueryTT(queryTT, best float64, candidates ...float64) float64 {
+	bestAbs := math.Abs(eventUTQueryTTDelta(best, queryTT))
+	for _, candidate := range candidates {
+		candidateAbs := math.Abs(eventUTQueryTTDelta(candidate, queryTT))
+		if candidateAbs < bestAbs {
+			best = candidate
+			bestAbs = candidateAbs
+		}
+	}
+	return best
+}
+
+type phaseEventSearchFunc func(jde, degree float64, next uint8) float64
+type simpleEventSearchFunc func(jde float64) float64
+
+func inclusiveLastPhaseEvent(jde, degree float64, fn phaseEventSearchFunc) float64 {
+	last := fn(jde, degree, 0)
+	next := fn(jde, degree, 1)
+	if eventUTQueryBeforeOrEqual(next, jde) && eventUTQueryAfterOrEqual(next, jde) {
+		return next
+	}
+	if eventUTQueryBeforeOrEqual(last, jde) {
+		return last
+	}
+	return last
+}
+
+func inclusiveNextPhaseEvent(jde, degree float64, fn phaseEventSearchFunc) float64 {
+	last := fn(jde, degree, 0)
+	if eventUTQueryBeforeOrEqual(last, jde) && eventUTQueryAfterOrEqual(last, jde) {
+		return last
+	}
+	next := fn(jde, degree, 1)
+	if eventUTQueryAfterOrEqual(next, jde) {
+		return next
+	}
+	return next
+}
+
+func inclusiveLastSimpleEvent(jde float64, lastFn, nextFn simpleEventSearchFunc) float64 {
+	last := lastFn(jde)
+	next := nextFn(jde)
+	if eventUTQueryBeforeOrEqual(next, jde) && eventUTQueryAfterOrEqual(next, jde) {
+		return next
+	}
+	if eventUTQueryBeforeOrEqual(last, jde) {
+		return last
+	}
+	return last
+}
+
+func inclusiveNextSimpleEvent(jde float64, lastFn, nextFn simpleEventSearchFunc) float64 {
+	last := lastFn(jde)
+	if eventUTQueryBeforeOrEqual(last, jde) && eventUTQueryAfterOrEqual(last, jde) {
+		return last
+	}
+	next := nextFn(jde)
+	if eventUTQueryAfterOrEqual(next, jde) {
+		return next
+	}
+	return next
+}