Unify error handling and HTTP statuses

Signed-off-by: Sean Du <do4suki@gmail.com>

internal/handler/api/challenge/info.go

@@ -2,13 +2,14 @@ package challenge
 
 import (
 	challengeapischema "honoka-chan/internal/schema/api/challenge"
+	"net/http"
 	"time"
 )
 
 func challengeInfo() (res any, err error) {
 	res = challengeapischema.InfoResp{
 		Result:     []any{},
-		Status:     200,
+		Status:     http.StatusOK,
 		CommandNum: false,
 		TimeStamp:  time.Now().Unix(),
 	}