Refactor editor rendering contracts

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

@@ -48,9 +48,13 @@ incomplete:
   code to load built-in PNGs, title-bar branding, or executable-relative
   capture output paths.
 - Scene viewport shader paths now flow through runtime initialization. The
-  scene viewport feature builds the paths from the runtime repo root and
+  viewport runtime service builds the paths from the runtime repo root and
   injects them into the render service/pass bundle instead of letting render
   passes infer source-tree paths from a compile-time repo-root macro.
+- Editor icon and viewport runtime contracts now live under
+  `editor/app/Core/Assets` and `editor/app/Core/Viewport`. Concrete icon
+  loading, viewport host services, scene viewport rendering, render targets,
+  and object-id picking stay under `editor/app/Rendering`.
 - Feature panels no longer use `Composition/EditorContext.h` directly. The
   app-core and app feature/viewport test targets now exercise `XCEditorCore`
   outside the executable host.
@@ -105,9 +109,13 @@ 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/Rendering`, `app/Scene`, `app/Services`,
-  `app/Support`, `app/Host/Interfaces`, `app/Host/Win32`, and
-  `app/Host/D3D12`; only executable-host code consumes `app/Bootstrap`.
+  `app/Windowing`, `app/Scene`, `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
+  `XCEditorCoreRendering` object library. `XCEditorCore` consumes the object
+  files but does not expose `app/Rendering` to Composition, Features, or Core
+  sources.
 - `editor_app_core_tests` now links `XCEditorCore` directly and uses explicit
   app module include roots. Its initial suite covers host command routing,
   project runtime, shell asset validation, project browser model, hierarchy
@@ -143,11 +151,13 @@ The refactor should converge on this shape:
 ```text
 editor/app/
   Core/
+    Assets/
     Commands/
     Panels/
     Scene/
     State/
     UtilityWindows/
+    Viewport/
     Windowing/
     WorkspacePanels/
 
@@ -175,6 +185,10 @@ editor/app/
     Win32/
     D3D12/
 
+  Rendering/
+    Assets/
+    Viewport/
+
   Bootstrap/
   Support/
 ```
@@ -183,6 +197,12 @@ This is a convergence target, not a requirement to move every file at once.
 The first cut should only move contracts that are already acting as global app
 interfaces.
 
+Same domain names under different layers are acceptable only when the layer
+meaning is explicit and build-checked: `Core/Viewport` is the shared contract
+surface, while `Rendering/Viewport` is the concrete implementation. If a
+Composition or Feature file needs a viewport concept, it should include the
+Core contract, not the concrete Rendering path.
+
 ## Dependency Rules
 
 The final direction should be:
@@ -197,6 +217,12 @@ Within `XCEditorCore`:
   `XCUIEditor`.
 - `Composition` must not include concrete feature panel headers.
 - `Features` may depend on `Core`, `Services`, and `XCUIEditor`.
+- `Composition` and `Features` must not include concrete `app/Rendering/**`
+  headers. They should use `Core/Assets/EditorIconService.h` and
+  `Core/Viewport/**` contracts.
+- `app/Rendering/**` may depend on `Core`, `Host/Interfaces`, `XCUIEditor`,
+  and engine renderer/editor support. It implements Core contracts and is wired
+  from `Application`.
 - `Services` must not depend on `Features`.
 - `State` must not depend on `Composition`.
 - `Windowing` may depend on `Core`, `Composition` interfaces, and
@@ -458,7 +484,7 @@ 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 viewport shader paths are runtime configuration now. Build them from
-  the runtime repo root in `SceneViewportFeature`, inject them into
+  the runtime repo root in the viewport runtime service, inject them into
   `SceneViewportRenderService`, and keep grid/selection render passes from
   inferring source-tree paths with compile-time macros or `__FILE__`.
 
@@ -554,8 +580,25 @@ Completed cuts:
   scene viewport request contract without depending on `app/Rendering/**`, and
   `editor_app_core_tests` no longer needs the app rendering include root to
   validate scene runtime behavior.
-- Scene viewport shader/resource paths are now injected from
-  `SceneViewportFeature` into `SceneViewportRenderService` and
+- Editor icon contracts now live under
+  `editor/app/Core/Assets/EditorIconService.h`. `BuiltInIcons` remains the
+  concrete `editor/app/Rendering` implementation, and panels/tool overlays
+  resolve icons through the contract instead of loading resource files or
+  naming concrete icon storage.
+- Viewport runtime contracts now live under `editor/app/Core/Viewport/**`.
+  `SceneViewportFeature` consumes `EditorSceneViewportRuntime`, while
+  `ViewportHostService` and `SceneViewportRenderService` stay concrete
+  rendering implementations behind `CreateEditorViewportRuntimeServices()`.
+- `Application` injects `CreateEditorIconService()` and
+  `CreateEditorViewportRuntimeServices()` into `EditorShellRuntime`, making
+  the executable startup path the only place that names those concrete
+  rendering factories.
+- `app/Rendering/**` now builds as `XCEditorCoreRendering`, a dedicated object
+  library consumed by `XCEditorCore`. This keeps rendering behavior in the
+  product core while preventing Composition/Features/Core from regaining an
+  `app/Rendering` include root.
+- Scene viewport shader/resource paths are now injected from the viewport
+  runtime service into `SceneViewportRenderService` and
   `SceneViewportRenderPassBundle`. The concrete grid and selection-outline
   passes no longer depend on `XCUIEDITOR_REPO_ROOT` or `__FILE__` source-tree
   fallback logic to find editor shaders.
@@ -615,6 +658,8 @@ The refactor is complete when:
 - `XCEditor` executable source is limited to host startup and concrete
   platform/render backend wiring.
 - `Composition` no longer includes concrete feature panel headers.
+- `Composition` and `Features` no longer include concrete `app/Rendering/**`
+  headers; icon and viewport use flows through Core contracts.
 - `Windowing` no longer includes concrete composition runtime/state headers;
   it depends on `Core/Windowing` composition interfaces instead.
 - `Services` no longer include `Features/**`.