Windowed reconcile-run history with per-provider counts + errors

Drives the internal-admin "Reconcile runs" page. Returns one row per run in [since, now], newest-first, with derived `durationMs` / `errorCount` / `errorsByProvider`. Window defaults to trailing 24h; `limit` clamped to [1, 500]. Backed by the `reconcile_runs_started` (started_at DESC) index — this query is hot. Sortable: startedAt, durationMs. Default sort: -startedAt.