chore(application): extract appearance controller and unify UI flow

- Refactor UI application architecture: extracted appearance controller into ui_services.hpp + implementation updates
- Update UI components and managers to use new service layer:
  - `action_bar_panel`, `auth_screen`, `character_screen`, `chat_panel`, `combat_ui`, `dialog_manager`, `game_screen`, `settings_panel`, `social_panel`, `toast_manager`, `ui_manager`, `window_manager`
- Adjust core application entrypoints:
  - application.cpp
- Update component implementations for new controller flow:
  - action_bar_panel.cpp, `chat_panel.cpp`, `combat_ui.cpp`, `dialog_manager.cpp`, `game_screen.cpp`, `settings_panel.cpp`, `social_panel.cpp`, `toast_manager.cpp`, `window_manager.cpp`

These staged changes implement a major architectural refactor for UI/appearance controller separation

include/ui/ui_services.hpp

@@ -0,0 +1,55 @@
+#pragma once
+
+namespace wowee {
+
+// Forward declarations
+namespace core { 
+    class Window;
+    class EntitySpawner;
+    class AppearanceComposer;
+    class WorldLoader;
+}
+namespace rendering { class Renderer; }
+namespace pipeline { class AssetManager; }
+namespace game { 
+    class GameHandler;
+    class ExpansionRegistry;
+}
+namespace addons { class AddonManager; }
+namespace audio { class AudioCoordinator; }
+
+namespace ui {
+
+/**
+ * UI Services - Dependency injection container for UI components.
+ * 
+ * Section 3.5: Break the singleton Phase B
+ * 
+ * Replaces Application::getInstance() calls throughout UI code.
+ * Application creates this struct and injects it into UIManager,
+ * which propagates it to GameScreen and all child UI components.
+ * 
+ * Owned by Application, shared as const pointers (non-owning).
+ */
+struct UIServices {
+    core::Window* window = nullptr;
+    rendering::Renderer* renderer = nullptr;
+    pipeline::AssetManager* assetManager = nullptr;
+    game::GameHandler* gameHandler = nullptr;
+    game::ExpansionRegistry* expansionRegistry = nullptr;
+    addons::AddonManager* addonManager = nullptr;
+    audio::AudioCoordinator* audioCoordinator = nullptr;
+    
+    // Extracted classes (also available individually for Phase A compatibility)
+    core::EntitySpawner* entitySpawner = nullptr;
+    core::AppearanceComposer* appearanceComposer = nullptr;
+    core::WorldLoader* worldLoader = nullptr;
+    
+    // Helper to check if core services are wired
+    bool isValid() const {
+        return window && renderer && assetManager && gameHandler;
+    }
+};
+
+} // namespace ui
+} // namespace wowee