fix: weekbased calculation pdf report

with this change the time calculations for pdf reports should be better
line with the reports send as "week_report"

Backend/helper/system.go

@@ -20,6 +20,10 @@ func GetEnv(key, fallback string) string {
 	return fallback
 }
 
+func IsDebug() bool {
+	return GetEnv("GO_ENV", "production") == "debug"
+}
+
 type CacheItem struct {
 	value      any
 	expiration time.Time