fix: Add missing dirtyChunks variable and update rendering logic

js/main.js

@@ -65,8 +65,8 @@ function simulationLoop(timestamp) {
     fps = Math.round(1000 / deltaTime);
     document.getElementById('fps').textContent = `FPS: ${fps}`;
     
-    // Update physics
-    updatePhysics();
+    // Update physics with timestamp for rate limiting
+    updatePhysics(timestamp);
     
     // Render
     render();