docs: annotate all shared frontend modules in Chinese

app/lib/useWithdrawAvailability.js

@@ -1,3 +1,4 @@
+/** 余额/推广提现入口可用性；按场景分别缓存规则，复用提现对话框中的规则判定。 */
 import { computed } from "vue";
 import { useState } from "#app";
 import { useApi } from "~/lib/auth.js";
@@ -16,6 +17,7 @@ function i(i = ``) {
     s = computed(() => a.value.loading),
     c = computed(() => a.value.loaded),
     l = computed(() => a.value.error);
+  // 已成功加载默认不重取，e 可强制刷新；失败保持 loaded=false，允许后续重试。
   async function u(e = !1) {
     if (!(a.value.loading || (a.value.loaded && !e))) {
       ((a.value.loading = !0), (a.value.error = ``));