PM-5397: Preserve AI Engineering history dimensions

What was broken
AI Engineering stats could show challenge counts, but the profile challenge details view could still be empty because the member stats history response did not expose those rows under the configured AI Engineering rating path.

Root cause
When history rows were enriched with Challenge API metadata, configured rating-path rows kept their challenge id and name but had their stored track/type overwritten by the source challenge's native Challenge or Marathon Match dimensions.

What was changed
Preserve configured rating-path dimensions during history metadata enrichment so AI Engineering history remains under DATA_SCIENCE.AI Engineering while still receiving canonical challenge metadata.

Any added/updated tests
Added a StatisticsService regression test that verifies an AI Engineering rating-path history row stays under DATA_SCIENCE.AI Engineering after challenge metadata enrichment.

Author: jmgasper

src/services/StatisticsService.js

@@ -1265,6 +1265,21 @@ function filterUnifiedHistoryRowsToCompletedChallenges (rows, challengeMetadataB
   })
 }
 
+/**
+ * Check whether a history row belongs to a configured rating path.
+ * Rating-path rows intentionally keep their stored type even when the source
+ * challenge was a native Challenge or Marathon Match event.
+ * @param {Object} row unified history row annotated with stored track/type names
+ * @returns {boolean} true when the row should preserve its stored rating-path dimensions
+ */
+function isConfiguredRatingPathHistoryRow (row) {
+  return !!(
+    getConfiguredRatingPath(config.RATING_PATHS, row && row.typeName) ||
+    getConfiguredRatingPath(config.RATING_PATHS, row && row.typeId) ||
+    getConfiguredRatingPathByTypeId(config.RATING_PATHS, row && row.typeId)
+  )
+}
+
 /**
  * Attach canonical challenge ids and names to unified history rows before shaping
  * the response payload consumed by the profiles UI.
@@ -1292,7 +1307,7 @@ function enrichUnifiedHistoryRowsWithChallengeMetadata (rows, challengeMetadataB
         : _.get(challenge, 'legacyRecord.legacySystemId')
     )
     const preserveLegacyChallengeId = isLegacyNumericMarathonHistoryRow(row)
-    const dimension = challenge.trackId && challenge.typeId
+    const dimension = !isConfiguredRatingPathHistoryRow(row) && challenge.trackId && challenge.typeId
       ? resolveStatsDimensionForChallengeRow({
         trackId: String(challenge.trackId),
         typeId: String(challenge.typeId)

test/unit/StatisticsService.test.js

@@ -728,6 +728,66 @@ describe('statistics service unit tests', () => {
     }
   })
 
+  it('getHistoryStats should preserve configured rating path dimensions after challenge metadata enrichment', async () => {
+    const ratingDate = new Date('2026-06-18T05:41:34.931Z')
+    const { service, restore } = loadStatisticsService({
+      ratingPaths: [
+        { name: 'AI Engineering', track: 'DATA_SCIENCE', tags: ['AI', 'AI Exponential League'] }
+      ],
+      prismaStub: {
+        $queryRaw: async () => [],
+        memberStats: {
+          findMany: async () => [{
+            trackId: 'track-ds-id',
+            typeId: 'rating-path-ai-engineering',
+            challenges: 1,
+            mostRecentEventDate: ratingDate
+          }]
+        },
+        memberStatsHistory: {
+          findMany: async () => [{
+            trackId: 'track-ds-id',
+            typeId: 'rating-path-ai-engineering',
+            challengeId: 'ai-history-challenge',
+            challengeName: null,
+            newRating: 840,
+            eventDate: ratingDate,
+            placement: 1,
+            mostRecent: true
+          }]
+        }
+      },
+      challengeRows: [{
+        id: 'ai-history-challenge',
+        legacyId: null,
+        name: 'AI Engineering Challenge',
+        status: 'COMPLETED',
+        trackId: 'track-dev-id',
+        typeId: 'type-challenge-id',
+        endDate: ratingDate,
+        track: { name: 'Development' },
+        type: { name: 'Challenge' },
+        metadata: [],
+        legacyRecord: null
+      }]
+    })
+
+    try {
+      const result = await service.getHistoryStats({ isMachine: true }, 'devtest1400', {})
+
+      result.should.have.length(1)
+      should.exist(result[0].DATA_SCIENCE)
+      should.exist(result[0].DATA_SCIENCE['AI Engineering'])
+      result[0].DATA_SCIENCE['AI Engineering'].history.should.have.length(1)
+      result[0].DATA_SCIENCE['AI Engineering'].history[0].challengeId.should.equal('ai-history-challenge')
+      result[0].DATA_SCIENCE['AI Engineering'].history[0].challengeName.should.equal('AI Engineering Challenge')
+      result[0].DATA_SCIENCE['AI Engineering'].history[0].newRating.should.equal(840)
+      should.not.exist(result[0].DEVELOP)
+    } finally {
+      restore()
+    }
+  })
+
   it('rerateMemberStats should route configured rating paths to the Marathon Match engine', async () => {
     let capturedOptions
     const { service, restore } = loadStatisticsService({