Move editor scene runtime under services

docs/plan/editor-core-refactor-plan.md

@@ -109,7 +109,7 @@ Completed boundary cuts:
 - The private `editor/app` compatibility include root is gone from
   `XCEditorCore` and `XCEditor`. App implementation files now include through
   explicit module roots such as `app/Composition`, `app/Features`,
-  `app/Windowing`, `app/Scene`, `app/Services`, `app/Support`,
+  `app/Windowing`, `app/Services`, `app/Support`,
   `app/Host/Interfaces`, `app/Host/Win32`, and `app/Host/D3D12`; only
   executable-host code consumes `app/Bootstrap`.
 - Concrete `app/Rendering/**` files now build through the
@@ -346,7 +346,7 @@ Initial contents:
 - `app/Composition/**`
 - `app/Features/**`
 - `app/Project/**` or `app/Services/Project/**`
-- `app/Scene/**` or `app/Services/Scene/**`
+- `app/Services/Scene/**`
 - `app/Core/UtilityWindows/**`
 - `app/Core/Windowing/**`
 - `app/Windowing/**` core files that do not require Win32 or D3D12
@@ -469,13 +469,20 @@ Completed:
 ```text
 Rendering/Viewport/SceneViewportRenderRequest.h
     -> Core/Scene/SceneViewportRenderRequest.h
+
+Scene/EditorSceneRuntime.h
+Scene/EditorSceneBridge.h
+Scene/SceneToolState.h
+Scene/SceneViewportCameraController.h
+    -> Services/Scene/
 ```
 
 Current shape:
 
 ```text
 Core/Scene/SceneViewportRenderRequest.h
-Scene/EditorSceneRuntime.h
+Services/Scene/EditorSceneRuntime.h
+Services/Scene/EditorSceneBridge.h
 Rendering/Viewport/SceneViewportRenderService.h
 ```
 
@@ -483,6 +490,9 @@ Rendering/Viewport/SceneViewportRenderService.h
 not a rendering implementation detail. Keep future scene-to-viewport request
 values under `Core/Scene` so scene services can build requests without taking
 an `app/Rendering/**` include dependency.
+Scene runtime, scene bridge, scene tool state, and scene viewport camera
+control are service-layer implementation and live under `Services/Scene`;
+the app root no longer owns a concrete `Scene` service directory.
 - Scene viewport shader paths are runtime configuration now. Build them from
   the runtime repo root in the viewport runtime service, inject them into
   `SceneViewportRenderService`, and keep grid/selection render passes from