feat(analytics): add event definition for gkg_query_executed

Summary

Adds the event definition YAML for the gkg_query_executed Snowplow tracking event. This event is emitted when a query call to the webserver (query_graph and get_graph_schema) is executed, and is part of instrumenting GKG for product analytics.

Changes

• config/events/gkg_query_executed.yml - Defines the gkg_query_executed event with:
  • Identifiers: namespace and user
  • Contexts: orbit_common and orbit_query
  • Product group: knowledge_graph
  • Available on all tiers (free, premium, ultimate)
  • Classification: duo
  • Milestone: 19.0

Motivation

This is part of the effort to instrument GKG for product analytics (Snowplow), enabling visibility into query-level usage. The event definition follows the GitLab Internal Events standard and will allow the event to be visualised in the metric dictionary once config/events definitions are in place.

Related

• Issue: gitlab-org/gitlab#598125 (closed) (Instrument first snowplow tracking event in GKG)
• Epic: gitlab-org#21189 (Instrument GKG for Product Analytics (Snowplow))
• Epic: gitlab-org#20357 (GKG Core Development Workstream)