docs(service-analytics): list $between in the preview evaluator's declared scope

The module's scope comment enumerated the operators the preview supports
and omitted $between — accurately, since it had no case and fell through
to the permissive default. Now that it has one, the list has to say so.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EkL3RGJrzjLEGURsLxfS2f

Author: claude

packages/services/service-analytics/src/preview-evaluator.ts

@@ -9,7 +9,7 @@
 //
 // Scope (deliberately the dataset-query subset, not a general engine):
 //   • Mongo-style `where` filters ($eq implicit, $ne/$gt/$gte/$lt/$lte/
-//     $in/$nin/$contains, $and/$or/$not)
+//     $between/$in/$nin/$contains, $and/$or/$not)
 //   • timeDimensions date-range filtering + granularity bucketing
 //     (day/week/month/quarter/year)
 //   • group-by dimensions; count / countDistinct / sum / avg / min / max