refactor: align frontend ownership boundaries

Close audit gaps across API drift, query policy, UI, and tests.

src/entities/broker-operation/model/display.ts

@@ -0,0 +1,53 @@
+import { formatMoney } from "@/shared/lib";
+import type { BrokerageOperation } from "../api/useBrokerageOperations";
+
+type PaymentPresentation = {
+	amount: string;
+	label: string;
+	tone: "positive" | "negative" | "neutral";
+};
+
+function entryLabelKey(operation: BrokerageOperation): string {
+	if (operation.category === "income")
+		return operation.type === "OPERATION_TYPE_COUPON"
+			? "ledger.entryLabel.income.coupon"
+			: "ledger.entryLabel.income.dividend";
+	return `ledger.category.${operation.category}`;
+}
+
+function paymentPresentation(
+	operation: BrokerageOperation,
+): PaymentPresentation {
+	if (!operation.payment)
+		return {
+			amount: "—",
+			label: "ledger.noMoney",
+			tone: "neutral",
+		};
+	if (isZeroDecimal(operation.payment.value))
+		return {
+			amount: formatMoney(operation.payment),
+			label: "ledger.noMoney",
+			tone: "neutral",
+		};
+	if (operation.payment.value.startsWith("-"))
+		return {
+			amount: `−${formatMoney({
+				...operation.payment,
+				value: operation.payment.value.slice(1),
+			})}`,
+			label: entryLabelKey(operation),
+			tone: "negative",
+		};
+	return {
+		amount: `+${formatMoney(operation.payment)}`,
+		label: entryLabelKey(operation),
+		tone: "positive",
+	};
+}
+
+function isZeroDecimal(value: string): boolean {
+	return /^-?0(?:\.0+)?$/.test(value);
+}
+
+export { paymentPresentation };