fix(terrain): main game also propagates MODF scale to WMO instances

Mirrors the editor's WMO scale fix. WMOReady gains a scale field that
is computed from the loaded MODF placement.scale (u16 / 1024) and
forwarded to wmoRenderer->createInstance(). Without this the main
game ignored MODF scale even on WotLK ADTs that use it.

include/rendering/terrain_manager.hpp

@@ -99,6 +99,7 @@ struct PendingTile {
         pipeline::WMOModel model;
         glm::vec3 position;
         glm::vec3 rotation;
+        float scale = 1.0f;
     };
     std::vector<WMOReady> wmoModels;