Initial public release

Aurum — a self-hosted personal finance operating system: cash flow,
net worth tracking, budgets, goals, recurring payments, reports,
proactive alerts, and a compound-interest returns calculator, all
bilingual (RU/EN) and mobile-first. Ships as a three-container Docker
Compose stack (Postgres + FastAPI + nginx-served React frontend).

See README.md for setup and CONTRIBUTING.md for development.

frontend/src/lib/format.ts

@@ -0,0 +1,46 @@
+import { getCurrency, getLanguage, type Language } from "@/lib/i18n";
+
+/** Maps our app language to the Intl locale used for number/date formatting. */
+export function getIntlLocale(language: Language = getLanguage()): string {
+  return language === "ru" ? "ru-RU" : "en-US";
+}
+
+// `currency` defaults to the app's primary currency setting (Settings page)
+// — call sites only need to pass it explicitly when formatting a value known
+// to be in a *different* currency than that setting.
+export function formatCurrency(amount: number | string, currency: string = getCurrency()): string {
+  const value = typeof amount === "string" ? Number(amount) : amount;
+  return new Intl.NumberFormat(getIntlLocale(), {
+    style: "currency",
+    currency,
+    maximumFractionDigits: 0,
+  }).format(value);
+}
+
+export function formatSignedCurrency(amount: number | string, currency: string = getCurrency()): string {
+  const value = typeof amount === "string" ? Number(amount) : amount;
+  const sign = value > 0 ? "+" : "";
+  return `${sign}${formatCurrency(value, currency)}`;
+}
+
+const MONTH_LABELS_EN = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"] as const;
+const MONTH_LABELS_RU = ["Янв", "Фев", "Мар", "Апр", "Май", "Июн", "Июл", "Авг", "Сен", "Окт", "Ноя", "Дек"] as const;
+
+export function getMonthLabels(language: Language): readonly string[] {
+  return language === "ru" ? MONTH_LABELS_RU : MONTH_LABELS_EN;
+}
+
+export function formatTransactionDate(isoDate: string): string {
+  const date = new Date(`${isoDate}T00:00:00`);
+  return new Intl.DateTimeFormat(getIntlLocale(), { month: "short", day: "numeric" }).format(date);
+}
+
+/** Russian noun pluralization: pick the right form for 1/2-4/5+ (with the
+ * 11-14 exception), e.g. pluralizeRu(3, "актив", "актива", "активов"). */
+export function pluralizeRu(count: number, one: string, few: string, many: string): string {
+  const mod10 = count % 10;
+  const mod100 = count % 100;
+  if (mod10 === 1 && mod100 !== 11) return one;
+  if (mod10 >= 2 && mod10 <= 4 && (mod100 < 12 || mod100 > 14)) return few;
+  return many;
+}