feat: add initial balance support to accounts, enhancing account management and balance calculations across components

lib/account-utils.ts

@@ -0,0 +1,9 @@
+import type { Account } from "./types";
+
+/**
+ * Calcule le solde réel d'un compte en incluant le solde initial
+ */
+export function getAccountBalance(account: Account): number {
+  return (account.initialBalance || 0) + account.balance;
+}
+