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/get.md

@@ -0,0 +1,25 @@
+# Get
+
+Get the singleton SceneManager instance.
+
+## Syntax
+
+```cpp
+static SceneManager& Get();
+```
+
+## Returns
+
+Returns a reference to the singleton `SceneManager` instance.
+
+## Remarks
+
+Access the SceneManager singleton through this static method. The SceneManager is created on first access.
+
+## Examples
+
+```cpp
+void Example() {
+    SceneManager& manager = SceneManager::Get();
+}
+```