feat(editor): open terrain format integrated into export workflow

- File > Export Open Format (.wot/.whm) menu item for standalone export
- Every zone export (Ctrl+S, Export Zone) now also writes .wot/.whm
  alongside the ADT/WDT — dual format output
- Export package now contains: ADT + WDT + WOT + WHM + JSON files
- Both Blizzard-compatible (for existing servers) and open format
  (for wowee-native loading and redistribution)

tools/editor/editor_ui.cpp

@@ -158,6 +158,8 @@ void EditorUI::renderMenuBar(EditorApp& app) {
                 app.quickSave();
             if (ImGui::MenuItem("Export Zone...", nullptr, false, app.hasTerrainLoaded()))
                 showSaveDialog_ = true;
+            if (ImGui::MenuItem("Export Open Format (.wot/.whm)", nullptr, false, app.hasTerrainLoaded()))
+                app.exportOpenFormat("output");
             if (ImGui::MenuItem("Export Content Pack (.wcp)", nullptr, false, app.hasTerrainLoaded())) {
                 std::string wcpPath = "output/" + app.getLoadedMap() + ".wcp";
                 app.exportContentPack(wcpPath);