fix(editor): NPC ghost preview, scale control, frame sync for M2 rendering

- Ghost preview now shows in NPC mode (follows cursor with creature model)
- Added scale field to CreatureSpawn (default 1.0, slider 0.5-10x)
- NPC instances render at their configured scale
- Scale included in JSON save format
- M2Renderer::update() now runs AFTER beginFrame() so getCurrentFrame()
  returns the correct frame index — fixes instance SSBO mismatch that
  caused draws=0 despite loaded models

tools/editor/editor_viewport.cpp

@@ -242,7 +242,7 @@ void EditorViewport::rebuildObjects(const std::vector<PlacedObject>& objects,
                 m2ModelIds[npc.modelPath] = modelId;
             }
             glm::vec3 rotRad = glm::radians(glm::vec3(0, 0, npc.orientation));
-            m2Renderer_->createInstance(modelId, npc.position, rotRad, 1.0f);
+            m2Renderer_->createInstance(modelId, npc.position, rotRad, npc.scale);
         }
     }