fix: standardize currency and input selection styles

src/utils/currency.ts

@@ -0,0 +1,14 @@
+export function formatAmount(value: number) {
+  return value.toLocaleString('zh-CN', {
+    minimumFractionDigits: 3,
+    maximumFractionDigits: 3,
+  });
+}
+
+export function formatCents(cents?: number | null) {
+  return formatAmount((cents ?? 0) / 100);
+}
+
+export function formatYuan(cents?: number | null) {
+  return `¥${formatCents(cents)}`;
+}