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/components/transform-component/get-up.md

@@ -0,0 +1,30 @@
+# GetUp
+
+Get the up direction vector in world space.
+
+## Syntax
+
+```cpp
+Math::Vector3 GetUp() const;
+```
+
+## Returns
+
+Returns the up direction vector as a `Math::Vector3`.
+
+## Remarks
+
+Returns the up direction of this transform in world space, based on the world rotation. By convention, up is typically the positive Y axis direction.
+
+## See Also
+
+- [GetForward](get-forward)
+- [GetRight](get-right)
+
+## Examples
+
+```cpp
+void Example(TransformComponent* transform) {
+    Math::Vector3 up = transform->GetUp();
+}
+```