Prepare a draft batch that creates Median's chart of accounts in a new QuickBooks file (#2642)

Jacob 2026-09-28: for a client new to both Median and QuickBooks, Median's chart of accounts is mirrored into QuickBooks. Builds ONE draft write-back batch: a pending create_account item per Median account QuickBooks lacks (Name, AcctNum = Median code, AccountType/AccountSubType from the Median detail type; a sub-account's ParentRef is resolved from its parent's created QuickBooks Id at send time, so parents are created first), and a blocked item per account that is mapped instead (QUICKBOOKS_CHART_PUSH_ALREADY_IN_QUICKBOOKS; the mapping is recorded when the batch posts) or skipped (its reason code). Nothing is sent: the batch is approved and posted through the write-back batch routes, and each created account is read back and then recorded as a QuickBooks account mapping. Takes no body. 422 QUICKBOOKS_CHART_PUSH_ESTABLISHED_FILE when QuickBooks has transactions before the cutoff, QUICKBOOKS_CHART_PUSH_NO_INVENTORY before a completed QuickBooks read, QUICKBOOKS_CHART_PUSH_INVENTORY_UNVERIFIED when the latest completed read cannot be shown to hold every transaction (unverifiedInventory in the problem names the failed checks; posting an approved chart push re-applies the same rule and answers 409 with the same code), QUICKBOOKS_CHART_PUSH_NEWER_READ_UNFINISHED while a QuickBooks read started after that completed read is queued, running or failed (newerRunStatus in the problem; the preview still shows the file as new so it does not change during each read, and posting an approved chart push answers 409 with the same code until a newer read completes), QUICKBOOKS_CHART_PUSH_NOTHING_TO_CREATE when nothing is missing, QUICKBOOKS_WRITEBACK_NO_CUTOFF before a posting cutoff is set (only the preview runs without one); 409 when an account is already held by another batch.