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/handlers/getPendingUpcomingExpenses.ts

@@ -0,0 +1,7 @@
+import type { Context } from "hono";
+import { listPendingUpcomingExpenses } from "../expenses.service";
+
+export async function getPendingUpcomingExpensesHandler(c: Context) {
+  const result = await listPendingUpcomingExpenses();
+  return c.json(result);
+}