docs: Add Component, GameObject, TransformComponent and Scene API documentation

- Add Component class documentation with lifecycle methods
- Add GameObject class documentation with component system
- Add TransformComponent documentation with transform methods
- Add Scene class documentation with GameObject management
- Add SceneManager singleton documentation with scene loading
- Update components.md overview with all component classes
- Update main.md navigation with Scene module

docs/api/scene/scene-manager/on-scene-loaded.md

@@ -0,0 +1,33 @@
+# OnSceneLoaded
+
+Event triggered when a scene is loaded.
+
+## Syntax
+
+```cpp
+Core::Event<Scene*>& OnSceneLoaded();
+```
+
+## Returns
+
+Returns a reference to the `Core::Event<Scene*>` for this event.
+
+## Remarks
+
+Subscribe to this event to be notified when a scene is loaded.
+
+## See Also
+
+- [OnSceneUnloaded](on-scene-unloaded)
+- [OnActiveSceneChanged](on-active-scene-changed)
+
+## Examples
+
+```cpp
+void Example() {
+    SceneManager& manager = SceneManager::Get();
+    manager.OnSceneLoaded().AddCallback([](Scene* scene) {
+        XC_LOG_INFO("Scene loaded: {}", scene->GetName());
+    });
+}
+```