adding reactivity and error message handling

src/components/swap-form.tsx

@@ -94,6 +94,8 @@ export function SwapForm() {
       const swapResult = swapAmounts[0]; // Get the first (and should be only) result
       const formattedAmount = formatUnits(swapResult.amountOut, selectedToToken.decimals);
       setToAmount(formattedAmount);
+    } else {
+      setToAmount('');
     }
   }, [swapAmounts, selectedToToken, hasInsufficientBalance]);