Decide a QuickBooks change (#2642)

take_qbo deactivates the link so the next activity import re-imports QuickBooks' version; Median's old entry must be reversed (followupStatus reversal_pending until the reversal flow is wired). keep_median keeps Median's version. When QuickBooks changed only a line's account or class or the memo of a pulled Purchase/Deposit, a draft write-back batch restoring Median's values is prepared (writeback_requested; it still needs approval and posting). Otherwise the restore stays writeback_pending with followupReason (client_must_correct_quickbooks or writeback_not_possible). dismiss records the reason and changes nothing now in Median or QuickBooks. For a change (not a deletion), Median's link then approves the reviewed QuickBooks version, so later reads and the activity import no longer flag it as changed. For an object Median pushed, it leaves the outstanding count at once, and the bank-feed push still writes Median's category to QuickBooks whenever the transaction changed after Median's last write to it, including before the dismissal. For an object Median pulled, it leaves the outstanding count with the next activity batch, and Median's entry keeps the earlier version; only the general-ledger parity check still shows a difference. A reason is required; the actor and time are recorded. When expectedAfterSourceObjectId is given and QuickBooks changed again since, or the review is no longer open, returns 409.