feat(expenses): add import functionality for expenses and total pending calculation

apps/backend/src/modules/expenses/expenses.service.ts

@@ -39,7 +39,7 @@ export function getCurrentYearMonthUTC(): { year: number; month: number } {
 export async function listPeriodicExpenses() {
   return prisma.periodicExpense.findMany({
     where: { isDeleted: false },
-    orderBy: { createdAt: "desc" },
+    orderBy: { description: "asc" },
   });
 }
 
@@ -163,6 +163,15 @@ export async function getMonthlyTotals(year: number, month: number) {
   };
 }
 
+export async function getTotalPending() {
+  const expenses = await prisma.expense.findMany({
+    where: { status: PaymentStatus.PENDING },
+    select: { amount: true },
+  });
+  const total = expenses.reduce((sum, e) => sum + Number(e.amount), 0);
+  return { total };
+}
+
 export async function generateExpensesForCurrentMonth() {
   const { year, month } = getCurrentYearMonthUTC();