Add recovery Excel export and automatic account detection

tests/date-utils.test.mjs

@@ -2,6 +2,7 @@ import assert from "node:assert/strict";
 import test from "node:test";
 import {
   formatShanghaiDate,
+  formatShanghaiToday,
   parseStoredDate,
 } from "../lib/date-utils.ts";
 
@@ -14,3 +15,7 @@ test("treats D1 CURRENT_TIMESTAMP values as UTC and displays Beijing time", () =
 test("keeps date-only deadlines on the intended Shanghai calendar date", () => {
   assert.match(formatShanghaiDate("2026-08-12"), /08\/12/);
 });
+
+test("formats the dashboard date from the Shanghai calendar", () => {
+  assert.equal(formatShanghaiToday(new Date("2026-08-04T16:30:00Z")), "8月5日");
+});