Double-entry has one invariant: the sum of every posting must be zero. Debits equal credits, always, across the whole ledger.
That makes reconciliation a single query rather than a project. Sum every debit, sum every credit, compare. If the difference is not zero, something wrote outside the ledger and you can find it immediately.
We expose that check in the admin console, because a check you can run is worth more than an assurance that someone ran it once.
The interesting part is not the query. It is that the design makes the check meaningful — a stored-balance system can be perfectly reconciled and still be wrong, because the balance was never derived from anything.