refactor: refactor foundation

src/entities/portfolio/model/display.test.ts

@@ -1,9 +1,11 @@
 import { describe, expect, it } from "vitest";
-import { formatDecimal, formatMoney } from "./display";
+import { formatMoney } from "./display";
 
 describe("portfolio display helpers", () => {
 	it("formats decimal strings without financial arithmetic", () => {
-		expect(formatDecimal("-1234567.89")).toBe("-1 234 567,89");
+		expect(formatMoney({ value: "-1234567.89", currency: "RUB" })).toBe(
+			"-1 234 567,89 ₽",
+		);
 		expect(formatMoney({ value: "10", currency: "RUB" })).toBe("10 ₽");
 		expect(formatMoney({ value: "0.5", currency: "USD" })).toBe("0,5 USD");
 		expect(formatMoney(null)).toBe("—");

src/entities/portfolio/model/display.ts

@@ -2,7 +2,7 @@ import type { Portfolio } from "../api/usePortfolio";
 
 type Money = Portfolio["totalsByCurrency"][number];
 
-export function formatDecimal(value: string): string {
+function formatDecimal(value: string): string {
 	const [integer, fraction] = value.split(".");
 	const sign = integer.startsWith("-") ? "-" : "";
 	const grouped = (sign ? integer.slice(1) : integer).replace(