Context

Express is the primary local executor for db / cluster-wide update-lookup streams (flag on).

Scope

• Add the recorder constructor parameter and the record* calls in ExpressSingleDocumentLookupExecutor.performLookup.
• The factory injects the updateLookupExpressStats cell.

Acceptance

A db/cluster-level stream with updates increments changeStreams.updateLookup.express.found / notFound + latency.

Tests

Extend the shared metrics jstest with the (flag on, db/cluster) branch: when the flag is on and
changeStreamPassthroughType() is kDb/kCluster, expect the express cell; flag off still expects
aggregation. No new file.

Dependencies

Depends on the metrics infrastructure ticket, ExpressSingleDocumentLookupExecutor (SERVER-128413), and
the Aggregation wiring ticket (which creates the shared jstest). Can run in parallel with the SBE
wiring ticket.