fix(ui): использовать серверное время и не подменять отсутствующий Ping

lib/speed-run-response.test.ts

@@ -15,3 +15,11 @@ test("invalid or foreign receipts cannot publish measurements", () => {
 test("invalid post-test ping rejects the whole receipt", () => {
   assert.throws(() => parseSpeedRunResponse({ ...receipt(10, 0), result: { ...receipt(10, 0).result, afterBtPing: { rttMs: null, lossPct: 101, error: null } } }, "run-1"))
 })
+
+test("server persistence time is validated while legacy receipt remains compatible", () => {
+  const base = receipt(10, 0)
+  const withTime = (createdAt: unknown) => ({ ...base, result: { ...base.result, createdAt } })
+  assert.equal(parseSpeedRunResponse(withTime("2026-10-07T07:00:00+07:00"), "run-1").createdAt, "2026-10-07T07:00:00+07:00")
+  assert.equal(parseSpeedRunResponse(base, "run-1").createdAt, undefined)
+  for (const value of [null, "", "yesterday", 123, "2026-10-07"]) assert.throws(() => parseSpeedRunResponse(withTime(value), "run-1"), /Результат операции неизвестен/)
+})