fix: Exclude FPU entries from carb statistics calculation

- Updated carbsForStats predicate to filter out isFPU entries
- Prevents double-counting of carbs when FPU conversion is enabled
- Fixes issue #580 where meal stats showed inflated carb counts

Model/Helper/CarbEntryStored+helper.swift

@@ -14,7 +14,7 @@ extension NSPredicate {
 
     static var carbsForStats: NSPredicate {
         let date = Date.threeMonthsAgo
-        return NSPredicate(format: "date >= %@", date as NSDate)
+        return NSPredicate(format: "date >= %@ AND isFPU == %@", date as NSDate, false as NSNumber)
     }
 
     static var carbsNotYetUploadedToNightscout: NSPredicate {