Add agent plataform flow metrics to GraphQL

Summary

Add agentPlatform field to aiMetrics GraphQL endpoint to expose Duo Agent Platform flow metrics.

Context

As part of delivering the Duo Agent Platform metrics dashboard for 18.7, we need to expose flow-level metrics through the GraphQL API. The agent_platform_sessions materialized view (introduced in !210808 (merged)) contains the necessary data.

Reference: https://gitlab.com/gitlab-org/gitlab/-/issues/570564#note_2899742603

Proposal

Add an agentPlatform attribute to the aiMetrics GraphQL endpoint that contains the following metrics per flow:

• Flow name - The name/identifier of the flow
• Number of sessions - Total count of sessions for this flow
• Average flow execution time - Avg (Median) flow execution time (minutes)
• Unique users - Count of distinct users who executed this flow
• Completion rate - Percentage of sessions that completed successfully

Query sample

query {
  group(fullPath:"gitlab-org") {
    aiMetrics(startDate: "2024-11-17", endDate: "2025-11-17") {
      agentPlataform {
        ...otherFields
        flowMetrics {
          flowName
          sessionCount
          averageExecutionTime
          uniqueUsersCount
          completionRate
        }
      }
    }
  }
}

Sample response

flowMetrics: {
  nodes: [
    { 
      flowName: 'chat',
      sessionCount: 10
      ...
    },
    {
      flowName: 'other',
      sessionCount: 11,
      ...
    },
    ...
  ]
}

Sorting Support

Add the ability to sort results based on:

• Number of sessions
• Average flow execution time
• Unique users

Data Source

Query the agent_platform_sessions materialized view to calculate these metrics based on the created_at_event, finished_at_event, and other relevant fields.