Add XCUI command routing and widget state models

docs/plan/XCUI_Phase_Status_2026-04-05.md

@@ -34,13 +34,15 @@ Old `editor` replacement is explicitly out of scope for this phase.
 - Shared editor collection primitive classification and metric helpers now also live under `engine/include/XCEngine/UI/Widgets` and `engine/src/UI/Widgets`, covering the current `ScrollView` / `TreeView` / `ListView` / `PropertySection` / `FieldRow` prototype taxonomy.
 - Shared single-selection state now also lives under `engine/include/XCEngine/UI/Widgets` and `engine/src/UI/Widgets` as `UISelectionModel`, so collection-style widget selection no longer has to stay private to `LayoutLab`.
 - Shared expansion state now also lives under `engine/include/XCEngine/UI/Widgets` and `engine/src/UI/Widgets` as `UIExpansionModel`, so collapsible tree/property-style widget state no longer has to stay private to `LayoutLab`.
+- Shared keyboard-navigation state now also lives under `engine/include/XCEngine/UI/Widgets` and `engine/src/UI/Widgets` as `UIKeyboardNavigationModel`, so list/tree/property-style widgets can share current-index, anchor, and home/end/step navigation rules instead of re-rolling them per sandbox.
+- Shared property-edit session state now also lives under `engine/include/XCEngine/UI/Widgets` and `engine/src/UI/Widgets` as `UIPropertyEditModel`, so editor-facing field rows can reuse begin/edit/commit/cancel transaction state instead of baking that directly into sandbox runtimes.
 - Core regression coverage now includes `UIContext`, layout, style, runtime screen player/system, and real document-host tests through `core_ui_tests`.
 
 Current gap:
 
 - Minimal schema self-definition support is landed, including consistency checks for enum/document-only schema metadata, but schema-driven validation for `.xcui` / `.xctheme` instances is still not implemented.
 - Shared widget/runtime instantiation is still thin and mostly editor-side.
-- Common widget primitives are still incomplete: shared text-input presentation/composition on top of the new text controller, multi-selection/keyboard-navigation/virtualized collection state on top of the new editor-primitive helpers, and native image/source-rect level APIs.
+- Common widget primitives are still incomplete: shared text-input presentation/composition on top of the new text controller, multi-selection/focus-traversal/virtualized collection state on top of the new editor-primitive helpers, and native image/source-rect level APIs.
 
 ### 2. Runtime/Game Layer
 
@@ -70,6 +72,8 @@ Current gap:
 - `LayoutLab` now consumes the shared `UIEditorCollectionPrimitives` helper layer for collection-widget tag classification, clipping flags, and default metric resolution instead of keeping that taxonomy private to the sandbox runtime.
 - `LayoutLab` now also consumes the shared `UISelectionModel` for click-selection persistence across collection-style widgets, and the diagnostics panel now exposes both hovered and selected element ids.
 - `LayoutLab` now also consumes the shared `UIExpansionModel` for tree expansion and property-section collapse, with reserved property headers, disclosure glyphs, and persisted click-toggle behavior in the sandbox runtime.
+- `new_editor` now also has an isolated `XCUIEditorCommandRouter` model with shortcut matching, enable predicates, and direct command invocation semantics covered by dedicated tests, ready for shell-frame integration.
+- `XCUI Demo` now exports pending per-frame command ids through `DrainPendingCommandIds()`, so editor-side hosts have a clean seam for observing demo/runtime command traffic without parsing draw data.
 - Panel diagnostics were expanded to clearly separate preview/runtime/input state and native vs legacy paths.
 - The editor bridge layer now has smoke coverage for swapchain after-UI rendering hooks and SRV-backed ImGui texture descriptor registration.
 - `Application` no longer owns the ImGui backend directly; window presentation now routes through `IWindowUICompositor` with an `ImGuiWindowUICompositor` implementation, which currently delegates to `IEditorHostCompositor` / `ImGuiHostCompositor`.
@@ -82,7 +86,7 @@ Current gap:
 
 - The shell is still ImGui-hosted.
 - Legacy hosted preview still depends on an active ImGui window context for inline presentation.
-- Editor-specialized widgets are still incomplete at the shared-module level: the authored prototypes exist, but virtualization, multi-selection/keyboard-navigation state, command routing, property editing models, toolbar/menu chrome, and icon-atlas widgets are not yet extracted into reusable XCUI modules.
+- Editor-specialized widgets are still incomplete at the shared-module level: the authored prototypes exist, but virtualization, multi-selection/focus traversal, toolbar/menu chrome, and icon-atlas widgets are not yet extracted into reusable XCUI modules, and the new keyboard-navigation/property-edit/command-routing models are still only partially integrated.
 
 ## Validated This Phase
 
@@ -90,10 +94,11 @@ Current gap:
 - `new_editor_xcui_layout_lab_runtime_tests`: `9/9`
 - `new_editor_xcui_rhi_command_compiler_tests`: `6/6`
 - `new_editor_xcui_rhi_render_backend_tests`: `5/5`
-- `new_editor_xcui_hosted_preview_presenter_tests`: `12/12`
-- `new_editor_imgui_window_ui_compositor_tests`: `5/5`
+- `new_editor_xcui_hosted_preview_presenter_tests`: `14/14`
+- `new_editor_imgui_window_ui_compositor_tests`: `7/7`
+- `new_editor_xcui_editor_command_router_tests`: `5/5`
 - `XCNewEditor` Debug target builds successfully
-- `core_ui_tests`: `38 total` (`36` passed, `2` skipped because `KeyCode::Delete` currently aliases `Backspace`)
+- `core_ui_tests`: `49 total` (`47` passed, `2` skipped because `KeyCode::Delete` currently aliases `Backspace`)
 - `scene_tests`: `68/68`
 - `core_ui_style_tests`: `5/5`
 - `ui_resource_tests`: `11/11`
@@ -108,6 +113,8 @@ Current gap:
 - Common-core `UIEditorCollectionPrimitives` extraction now owns the editor collection tag taxonomy and default metric resolution used by current `LayoutLab` widget prototypes, with dedicated `core_ui_tests` coverage.
 - Common-core `UISelectionModel` extraction now owns reusable single-selection state for collection-style widgets, with dedicated `core_ui_tests` coverage.
 - Common-core `UIExpansionModel` extraction now owns reusable expansion/collapse state for tree/property-style widgets, with dedicated `core_ui_tests` coverage.
+- Common-core `UIKeyboardNavigationModel` extraction now owns reusable current-index/anchor navigation state for collection-style widgets, with dedicated `core_ui_tests` coverage.
+- Common-core `UIPropertyEditModel` extraction now owns reusable property-field edit session state, including staged values and commit/cancel behavior, with dedicated `core_ui_tests` coverage.
 - Demo runtime text editing was extended with:
   - click-to-place caret
   - `Delete` support
@@ -118,6 +125,7 @@ Current gap:
 - LayoutLab editor-widget prototypes for tree/list/property-style sections with dedicated runtime coverage.
 - LayoutLab click-selection now persists through the shared `UISelectionModel`, including selected-state diagnostics and reusable visual selection feedback on cards, collection rows, and field rows.
 - LayoutLab tree expansion and property-section collapse now persist through the shared `UIExpansionModel`, including reserved property headers, disclosure glyphs, and runtime coverage for collapsed/expanded visibility.
+- `XCUIDemoRuntime` now exposes `DrainPendingCommandIds()` so hosts can observe emitted runtime commands in order across pointer/text interactions without scraping UI text or draw-command payloads.
 - Schema document support extended with:
   - retained `UISchemaDefinition` data on `UIDocumentModel`
   - artifact schema version bump for UI documents
@@ -162,6 +170,8 @@ Current gap:
   - `ImGuiHostCompositor`
   - `Application` frame/present flow routed through the compositor instead of direct `m_imguiBackend` ownership
 - The window-level XCUI compositor seam now also has a dedicated regression target around `ImGuiWindowUICompositor`, covering initialization, render-frame ordering, Win32 message forwarding, texture registration forwarding, and shutdown safety.
+- The window compositor and hosted-preview seams gained more edge-case coverage around no-UI render passes, compositor re-initialization/rebinding, partial logical-size fallback, and descriptor reuse for repeated queued-frame keys.
+- `new_editor` now has a dedicated `XCUIEditorCommandRouter` test target covering command registration, replacement, enable predicates, accelerator matching, and policy gates around focus/keyboard capture/text input.
 - `SceneRuntime` layered XCUI routing now has dedicated regression coverage for:
   - top-interactive layer input ownership
   - blocking/modal layer suppression of lower layers