Fix physics recorder crash when bodies are disposed during capture

Added defensive checks and try-catch to handle race conditions where physics
bodies are disposed between the filter check and property access. This commonly
happens with projectiles and destroyed asteroids.

Changes:
- Added null/undefined check for physicsBody in filter
- Added transformNode existence check before access
- Wrapped capture logic in try-catch to skip disposed objects
- Continue loop instead of crashing when object is disposed

Fixes TypeError: Cannot read properties of undefined (reading 'transformNode')

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

src/physicsRecorder.ts

@@ -155,11 +155,17 @@ export class PhysicsRecorder {
         const objects: PhysicsObjectState[] = [];
 
         // Get all physics-enabled meshes
-        const physicsMeshes = this._scene.meshes.filter(mesh => mesh.physicsBody !== null);
+        const physicsMeshes = this._scene.meshes.filter(mesh => mesh.physicsBody !== null && mesh.physicsBody !== undefined);
 
         for (const mesh of physicsMeshes) {
-            const body = mesh.physicsBody!;
+            const body = mesh.physicsBody;
 
+            // Double-check body still exists and has transformNode (can be disposed between filter and here)
+            if (!body || !body.transformNode) {
+                continue;
+            }
+
+            try {
                 // Get position
                 const pos = body.transformNode.position;
 
@@ -210,6 +216,10 @@ export class PhysicsRecorder {
                     mass: parseFloat(mass.toFixed(2)),
                     restitution: parseFloat(restitution.toFixed(2))
                 });
+            } catch (error) {
+                // Physics body was disposed during capture, skip this object
+                continue;
+            }
         }
 
         const snapshot: PhysicsSnapshot = {