migrate texture atlases to scoped ownership

- replace TextureAtlasManager and GlobalTextureAtlas with catalog-backed atlas ownership
  - make TextureAtlas and TextureRegion creation return explicit resource handles
  - let atlases retain their textures and regions through shared ownership
  - add atlas publication, lookup, removal, and enumeration to ResourceCatalog and ResourceScope
  - make TextureAtlasLoader publish atlases and regions into an explicit resource scope
  - move theme atlas ownership into each theme resource catalog
  - migrate maps, editors, examples, and tests away from the global atlas manager
  - add scope-aware Sprite pattern-loading overloads while preserving default-scope compatibility
  - fix re-entrant style-state invalidation when applying styles creates new widgets
  - add atlas ownership, scoped Sprite lookup, and style-state regression coverage
  - update the resource ownership plan and texture atlas editor launch configuration

src/tests/unit_tests/uiscenenode_tests.cpp

@@ -5,6 +5,7 @@
 #include <eepp/scene/scenemanager.hpp>
 #include <eepp/system/filesystem.hpp>
 #include <eepp/system/sys.hpp>
+#include <eepp/ui/uifiledialog.hpp>
 #include <eepp/ui/uiroot.hpp>
 #include <eepp/ui/uiscenenode.hpp>
 #include <eepp/ui/uithememanager.hpp>
@@ -364,3 +365,22 @@ UTEST( UISceneNode, NestedSceneInvalidationPropagatesToHostScene ) {
 
 	Engine::destroySingleton();
 }
+
+UTEST( UISceneNode, StyleStateUpdateAllowsWidgetCreation ) {
+	Engine::instance()->createWindow( WindowSettings( 1024, 768, "Style State Widget Creation Test",
+													  WindowStyle::Default, WindowBackend::Default,
+													  32, {}, 1, false, true ),
+									  ContextSettings( false, 0, 0, GLv_default, true, false ) );
+
+	UISceneNode* sceneNode = init_test_scene_node();
+	UIFileDialog* dialog = UIFileDialog::New();
+	dialog->setParent( sceneNode->getRoot() );
+
+	// Applying the select-button state creates its UIImage icon. The new widget invalidates style
+	// state while the current dirty-state pass is still being processed.
+	sceneNode->flushDirtyStyleAndLayout();
+
+	EXPECT_TRUE( dialog->getButtonOpen() != nullptr );
+
+	Engine::destroySingleton();
+}