feat: enhance transactions page with total amount and count display; integrate collapsible statistics card and update chart data handling

hooks/use-transactions-chart-data.ts

@@ -191,10 +191,25 @@ export function useTransactionsChartData({
     return categoryChartData;
   }, [transactionsData, metadata]);
 
+  // Calculate total amount and count from all filtered transactions
+  const totalAmount = useMemo(() => {
+    if (!transactionsData) return 0;
+    return transactionsData.transactions.reduce(
+      (sum, t) => sum + t.amount,
+      0
+    );
+  }, [transactionsData]);
+
+  const totalCount = useMemo(() => {
+    return transactionsData?.total || 0;
+  }, [transactionsData?.total]);
+
   return {
     monthlyData,
     categoryData,
     isLoading,
+    totalAmount,
+    totalCount,
   };
 }