feat(dashboard): add pending/upcoming expenses table

- Backend: GET /expenses/pending-upcoming returns PENDING expenses with dueDate <= today+5 days, classified as overdue/upcoming
- DashboardExpensesTable: groups by periodicExpenseId, shows summed totals with status badges, links to /expenses?periodicExpenseId=X
- Expenses route accepts ?periodicExpenseId search param and pre-selects it in the filter
- fix: BeloAnalysisPage DatePicker type mismatch

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

@@ -216,6 +216,27 @@ export async function getTotalPending() {
   return data;
 }
 
+export async function listPendingUpcomingExpenses() {
+  const now = new Date();
+  const today = new Date(Date.UTC(now.getUTCFullYear(), now.getUTCMonth(), now.getUTCDate(), 0, 0, 0, 0));
+  const fiveDaysLater = new Date(today);
+  fiveDaysLater.setUTCDate(fiveDaysLater.getUTCDate() + 5);
+
+  const data = await prisma.expense.findMany({
+    where: {
+      status: PaymentStatus.PENDING,
+      dueDate: { lte: fiveDaysLater },
+    },
+    include: { periodicExpense: true },
+    orderBy: { dueDate: "asc" },
+  });
+
+  return data.map((expense) => ({
+    ...expense,
+    dueType: expense.dueDate < today ? "overdue" as const : "upcoming" as const,
+  }));
+}
+
 export async function generateExpensesForCurrentMonth() {
   const { year, month } = getCurrentYearMonthUTC();