refactor: simplify calendar and form state

src/shared/lib/calendar.ts

@@ -9,4 +9,18 @@ function isValidPeriod(from: null | string, to: null | string) {
 	);
 }
 
-export { isValidPeriod };
+function moscowDate(value: Date): string {
+	const parts = new Intl.DateTimeFormat("en-CA", {
+		day: "2-digit",
+		month: "2-digit",
+		timeZone: "Europe/Moscow",
+		year: "numeric",
+	}).formatToParts(value);
+
+	const part = (type: string) =>
+		parts.find(item => item.type === type)?.value;
+
+	return `${part("year")}-${part("month")}-${part("day")}`;
+}
+
+export { isValidPeriod, moscowDate };