fix(streckkod+kvitto): sparad-bekraftelse, fettvarden, kvitto-antal

Streckkod / produktbidrag:
- Tydlig bekraftelse 'Sparad i delade katalogen - tack!' visas nu efter att en
  fotad produkt lasts av, sa man ser att bidraget gick fram (forut bara
  'Skanna igen' utan aterkoppling).
- Naringsetiketter laser nu ocksa enkelomattat och fleromattat fett (t.ex.
  olivolja visar tre fettrader). Nya valfria falt monounsaturatedFatG/
  polyunsaturatedFatG i NutritionValues + READ_NUTRITION_LABEL + prompt +
  produktpanelen. Obligatoriska EU-falt oforandrade.

Kvitto:
- Rader som ar samma vara (samma normaliserade namn + enhet) slas nu ihop till
  EN vara med ratt antal - '2 x mjolk' pa kvittot blir en vara a 2 st i stallet
  for tva rader a 1 st. Priser summeras, rabatter dras som forut. En kvittorad
  raknas som minst 1 exemplar aven om antal saknas.

Verifierat: typecheck hela repot gront, nutrition-engine 19/19, ai-contracts
24/24, worker 23/23, api 104/104, samt repro mot testdatabas (2 mjolk-rader ->
1 vara a 2; olivolja sparar fett/mattat/enkel-/fleromattat).

apps/mobile/src/app/barcode.tsx

@@ -29,6 +29,8 @@ type Nutrition = {
     carbsG: number;
     fatG: number;
     saturatedFatG: number;
+    monounsaturatedFatG?: number;
+    polyunsaturatedFatG?: number;
     fiberG: number;
     sugarG: number;
     saltG: number;
@@ -87,6 +89,7 @@ export default function BarcodeScreen() {
   const [product, setProduct] = useState<ProductInfo | null>(null);
   const [unknown, setUnknown] = useState(false);
   const [contributing, setContributing] = useState(false);
+  const [justContributed, setJustContributed] = useState(false);
   const [errorMsg, setErrorMsg] = useState<string | null>(null);
   // Synkron lås: hindrar att kamerans upprepade träffar startar parallella uppslag.
   const locked = useRef(false);
@@ -101,6 +104,7 @@ export default function BarcodeScreen() {
     lastGtin.current = gtin;
     setBusy(true);
     setErrorMsg(null);
+    setJustContributed(false);
     try {
       const result = await api<BarcodeScanResponse>("/v1/scans", {
         method: "POST",
@@ -177,6 +181,7 @@ export default function BarcodeScreen() {
       const found = await pollScan(created.scan.id);
       if (found) {
         setUnknown(false);
+        setJustContributed(true);
         setProduct(found);
       } else {
         // Behåll nuvarande vy (okänd/produkt) och visa felet som dialog.
@@ -197,6 +202,7 @@ export default function BarcodeScreen() {
     setProduct(null);
     setUnknown(false);
     setErrorMsg(null);
+    setJustContributed(false);
     locked.current = false;
     lastGtin.current = null;
   };
@@ -248,6 +254,11 @@ export default function BarcodeScreen() {
       {product && !contributing && (
         <View style={styles.panel}>
           <ScrollView contentContainerStyle={{ padding: spacing.lg, paddingBottom: spacing.md }}>
+            {justContributed && (
+              <View style={styles.savedBanner}>
+                <Small style={styles.savedText}>{t("barcode.contributing.saved")}</Small>
+              </View>
+            )}
             <Heading>{product.name}</Heading>
             {(product.brand || product.packageSizeValue) && (
               <Small style={styles.muted}>
@@ -269,6 +280,12 @@ export default function BarcodeScreen() {
                 <NutRow label={t("barcode.info.kcal")} value={`${Math.round(n.kcal)} kcal`} strong />
                 <NutRow label={t("barcode.info.fat")} value={fmtG(n.fatG)} />
                 <NutRow label={t("barcode.info.satfat")} value={fmtG(n.saturatedFatG)} sub />
+                {n.monounsaturatedFatG != null && (
+                  <NutRow label={t("barcode.info.monofat")} value={fmtG(n.monounsaturatedFatG)} sub />
+                )}
+                {n.polyunsaturatedFatG != null && (
+                  <NutRow label={t("barcode.info.polyfat")} value={fmtG(n.polyunsaturatedFatG)} sub />
+                )}
                 <NutRow label={t("barcode.info.carbs")} value={fmtG(n.carbsG)} />
                 <NutRow label={t("barcode.info.sugar")} value={fmtG(n.sugarG)} sub />
                 <NutRow label={t("barcode.info.fiber")} value={fmtG(n.fiberG)} />
@@ -426,4 +443,12 @@ const styles = StyleSheet.create({
   muted: { color: colors.textMuted },
   strong: { fontWeight: "700" },
   source: { color: colors.textMuted, fontStyle: "italic" },
+  savedBanner: {
+    backgroundColor: colors.primarySoft,
+    borderRadius: 10,
+    paddingVertical: spacing.xs,
+    paddingHorizontal: spacing.sm,
+    marginBottom: spacing.sm,
+  },
+  savedText: { color: colors.primary, fontWeight: "700" },
 });