fix: analysis controller was stealing stockfish from bg analysis

Root cause: useAnalysisController's useEngineAnalysis hook auto-runs
stockfish on every currentNode change. During drill play, each move
synced the node to the analysis controller, which called
stockfish.streamEvaluations() — killing the background analysis's
in-progress evaluation (the new call's stopEvaluation() terminates
the old generator).

Fix: only sync currentNode to the analysis controller when analysis
is actually active (post-drill continue-analyzing mode), not during
active drill play.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: ashtonanderson

src/pages/openings/index.tsx

@@ -182,12 +182,23 @@ const OpeningsPage: NextPage = () => {
     false, // Disable auto-saving on openings page
   )
 
-  // Sync analysis controller with current node
+  // Sync analysis controller with current node — only when analysis is active
+  // (post-drill continue-analyzing mode). During drill play, the analysis
+  // controller's auto-stockfish would conflict with background analysis.
   useEffect(() => {
-    if (controller.currentNode && analysisController.setCurrentNode) {
+    if (
+      controller.currentNode &&
+      analysisController.setCurrentNode &&
+      (controller.analysisEnabled || controller.continueAnalyzingMode)
+    ) {
       analysisController.setCurrentNode(controller.currentNode)
     }
-  }, [controller.currentNode, analysisController.setCurrentNode])
+  }, [
+    controller.currentNode,
+    controller.analysisEnabled,
+    controller.continueAnalyzingMode,
+    analysisController.setCurrentNode,
+  ])
 
   // Create game object for MovesContainer
   const gameForContainer = useMemo(() => {