- fix: Correct sun.TrueBo calculation, now using basic.HSunTrueBo for correct solar latitude

- fix: Rename GetSunDownTime to GetSunSetTime in basic/sun.go and update related calls/outputs
- fix: Update test cases to use new method and error constant names

- improve: Rename all DownTime/Down functions to SetTime/Set for consistency
- improve: Standardize ERR_XXX_NEVER_DOWN error constants to ERR_XXX_NEVER_SET, with ERR_XXX_NEVER_DOWN kept as compatibility alias
- improve: More standard naming for interfaces and errors to improve maintainability and readability

basic/sun_test.go

@@ -10,7 +10,7 @@ import (
 
 func Test_Jq(t *testing.T) {
 	data := GetJieqiLoops(2019, 24)
-	for i := 1; i < 25; i++ {
+	for i := 1; i < len(data); i++ {
 		fmt.Println(JDE2Date(data[i]))
 	}
 	//fmt.Println(JDE2Date(GetWHTime(2019, 10)))
@@ -144,7 +144,7 @@ func Test_SunRiseRound(t *testing.T) {
 func Test_SunDown(t *testing.T) {
 	jde := GetNowJDE()
 	for i := 10.0; i < 90.0; i += 0.3 {
-		fmt.Println(i, GetSunDownTime(jde, 115, float64(i), 8, 0, 0))
+		fmt.Println(i, GetSunSetTime(jde, 115, float64(i), 8, 0, 0))
 	}
 }