fix: resolve state management issues and memory leaks (#152)

This commit fixes several issues in the core state management:

1. Fix deleteNodesAction recursive call issue
   - Previously, the function recursively called get().deleteNodes()
     inside the set() callback, which could cause state inconsistencies.
   - Now collects all descendant IDs first in a separate pass, then
     deletes them all in a single batch operation.

2. Fix memory leak in use-scene temporal tracking
   - Module-level variables (prevPastLength, prevFutureLength,
     prevNodesSnapshot) persisted across store re-creations.
   - Now cleared in unloadScene() to release stale node references.
   - Added clearTemporalTracking() helper function.

3. Remove unused variable in wall-system
   - Removed debug variable 'useFrameNb' that was declared but never used.

4. Fix requestAnimationFrame in updateNodesAction
   - Previously used RAF without cleanup, causing multiple queued
     callbacks when updates happened rapidly.
   - Now uses a single tracked RAF with cancellation support.

Co-authored-by: hobostay <hobostay@users.noreply.github.com>
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

packages/core/src/systems/wall/wall-system.tsx

@@ -22,7 +22,6 @@ const csgEvaluator = new Evaluator()
 // WALL SYSTEM
 // ============================================================================
 
-let useFrameNb = 0
 export const WallSystem = () => {
   const dirtyNodes = useScene((state) => state.dirtyNodes)
   const clearDirty = useScene((state) => state.clearDirty)
@@ -35,7 +34,6 @@ export const WallSystem = () => {
     // Collect dirty walls and their levels
     const dirtyWallsByLevel = new Map<string, Set<string>>()
 
-    useFrameNb += 1
     dirtyNodes.forEach((id) => {
       const node = nodes[id]
       if (!node || node.type !== 'wall') return