feat: add environment variable switch for critical rate limit

middleware/rate-limit.go

@@ -102,7 +102,10 @@ func GlobalAPIRateLimit() func(c *gin.Context) {
 }
 
 func CriticalRateLimit() func(c *gin.Context) {
-	return rateLimitFactory(common.CriticalRateLimitNum, common.CriticalRateLimitDuration, "CT")
+	if common.CriticalRateLimitEnable {
+		return rateLimitFactory(common.CriticalRateLimitNum, common.CriticalRateLimitDuration, "CT")
+	}
+	return defNext
 }
 
 func DownloadRateLimit() func(c *gin.Context) {