Fix game objects rendering with player textures

When M2Renderer's descriptor pool was exhausted, batch.materialSet
would be VK_NULL_HANDLE and the bind was skipped, but the draw call
still executed using the previously bound descriptor set from
CharacterRenderer — causing game objects to render with the player's
skin/armor textures. Skip the entire batch instead.

src/rendering/m2_renderer.cpp

@@ -2381,11 +2381,11 @@ void M2Renderer::render(VkCommandBuffer cmd, VkDescriptorSet perFrameSet, const
                 }
             }
 
-            // Bind material descriptor set (set 1)
-            if (batch.materialSet) {
+            // Bind material descriptor set (set 1) — skip batch if missing
+            // to avoid inheriting a stale descriptor set from a prior renderer
+            if (!batch.materialSet) continue;
             vkCmdBindDescriptorSets(cmd, VK_PIPELINE_BIND_POINT_GRAPHICS,
                                     pipelineLayout_, 1, 1, &batch.materialSet, 0, nullptr);
-            }
 
             // Push constants
             M2PushConstants pc;