feat(editor): multi-select objects, time-of-day lighting, WOT loading

- Multi-select: Ctrl+Shift+Click adds objects to selection, transforms
  (move/rotate/scale/delete) operate on all selected objects at once
- Time-of-day slider (0-24h) with automatic sun angle, light color,
  ambient, fog, and sky color transitions (dawn/day/dusk/night)
- View > Sky/Lighting menu: color pickers for light/ambient/fog, fog
  distance sliders, preset buttons (Dawn/Noon/Dusk/Night)
- loadADT prefers WOT/WHM open format from custom_zones/output dirs
- Selection count display when multiple objects selected
- setSkyPreset now delegates to setTimeOfDay for consistency

tools/editor/object_placer.hpp

@@ -34,13 +34,18 @@ public:
     // Place object at world position
     void placeObject(const glm::vec3& position);
 
-    // Select object nearest to ray
+    // Select object nearest to ray (Shift adds to selection)
     int selectAt(const rendering::Ray& ray, float maxDist = 50.0f);
+    void addToSelection(int idx);
+    void toggleSelection(int idx);
     void clearSelection();
     int getSelectedIndex() const { return selectedIdx_; }
     PlacedObject* getSelected();
+    const std::vector<int>& getSelectedIndices() const { return selectedIndices_; }
+    size_t selectionCount() const { return selectedIndices_.size(); }
+    bool isMultiSelected() const { return selectedIndices_.size() > 1; }
 
-    // Transform selected
+    // Transform selected (operates on all selected objects)
     void moveSelected(const glm::vec3& delta);
     void rotateSelected(const glm::vec3& deltaDeg);
     void scaleSelected(float delta);
@@ -85,6 +90,7 @@ private:
     std::vector<PlacedObject> objects_;
     std::vector<int> undoStack_; // indices of recently placed objects
     int selectedIdx_ = -1;
+    std::vector<int> selectedIndices_;
     uint32_t uniqueIdCounter_ = 1;
     float placementRotY_ = 0.0f;
     float placementScale_ = 1.0f;