Sub-ticket for SERVER-87657.

Add the shared query-stats entry, store, and serialization changes needed to surface errors. Guard the new behavior under an IFR-eligible feature flag; error-path-specific updates will be handled in follow-on tickets. Specific changes:

• Add execCountErrored to the query stats entry and update execCount semantics to count both successes and errors.
• Add the internalQueryStatsMaxErrorCodesPerShape knob.
• Add a bounded per-shape error list implemented as an LRU-style cache that stores {code, count, latestSeenTimestamp} for up to internalQueryStatsMaxErrorCodesPerShape entries.
• In $queryStats output, serialize each stored error code as {code, codeName, count, latestSeenTimestamp}, resolving codeName via ErrorCodes::errorString() at read/serialization time.