perf: RAF-debounce setHoveredNodeId and skip hover during panning

Rapid mouse movement across the canvas fires multiple mouseout events
per frame, each triggering ~150 Zustand selector evaluations. This
coalesces hover updates into one per animation frame and skips them
entirely during canvas panning/dragging.

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

src/components/nodes/BaseNode.tsx

@@ -205,8 +205,14 @@ export function BaseNode({
           ${!fullBleed && selected && settingsExpanded ? "border-blue-500" : ""}
           ${className}
         `}
-        onMouseEnter={() => setHoveredNodeId(id)}
-        onMouseLeave={() => setHoveredNodeId(null)}
+        onMouseEnter={() => {
+          if (document.querySelector('.react-flow__pane.dragging')) return;
+          setHoveredNodeId(id);
+        }}
+        onMouseLeave={() => {
+          if (document.querySelector('.react-flow__pane.dragging')) return;
+          setHoveredNodeId(null);
+        }}
       >
         <div className={contentClassName ?? (fullBleed ? "flex-1 min-h-0 relative" : "px-3 pb-4 flex-1 min-h-0 overflow-hidden flex flex-col")}>{children}</div>
       </div>

src/store/workflowStore.ts

@@ -382,6 +382,10 @@ let nodeIdCounter = 0;
 let groupIdCounter = 0;
 let autoSaveIntervalId: ReturnType<typeof setInterval> | null = null;
 
+// RAF debounce for hover updates — coalesces rapid mouseenter/mouseleave events
+// into a single store update per animation frame
+let hoverRafId: number | null = null;
+
 // Track pending save-generation syncs to ensure IDs are resolved before workflow save
 const pendingImageSyncs = new Map<string, Promise<void>>();
 
@@ -526,7 +530,11 @@ const workflowStoreImpl: StateCreator<WorkflowStore> = (set, get) => ({
   },
 
   setHoveredNodeId: (id: string | null) => {
-    set({ hoveredNodeId: id });
+    if (hoverRafId !== null) cancelAnimationFrame(hoverRafId);
+    hoverRafId = requestAnimationFrame(() => {
+      hoverRafId = null;
+      if (get().hoveredNodeId !== id) set({ hoveredNodeId: id });
+    });
   },
 
   addNode: (type: NodeType, position: XYPosition, initialData?: Partial<WorkflowNodeData>) => {