Add dock host interaction contract validation

tests/UI/Editor/integration/README.md

@@ -17,6 +17,7 @@ Layout:
 - `shell/workspace_shell_compose/`: split/tab/panel shell compose only
 - `shell/editor_shell_compose/`: editor root shell compose only
 - `shell/editor_shell_interaction/`: editor root shell interaction only
+- `shell/dock_host_basic/`: DockHost interaction contract only
 - `shell/menu_bar_basic/`: menu bar open/close/hover/dispatch only
 - `shell/context_menu_basic/`: context menu root/submenu/dismiss/dispatch only
 - `shell/panel_frame_basic/`: panel frame layout/state/hit-test only
@@ -47,6 +48,11 @@ Scenarios:
   Executable: `XCUIEditorShellInteractionValidation.exe`
   Scope: root shell interaction only; menu bar root switching, submenu hover chain, outside/Esc dismiss, command hook, and workspace input shielding
 
+- `editor.shell.dock_host_basic`
+  Build target: `editor_ui_dock_host_basic_validation`
+  Executable: `XCUIEditorDockHostBasicValidation.exe`
+  Scope: `UpdateUIEditorDockHostInteraction(...)` basic contract only; splitter drag, tab activate/close, standalone panel activate/close, pointer capture/release request, workspace active-panel sync
+
 - `editor.shell.menu_bar_basic`
   Build target: `editor_ui_menu_bar_basic_validation`
   Executable: `XCUIEditorMenuBarBasicValidation.exe`
@@ -129,6 +135,9 @@ Selected controls:
 - `shell/editor_shell_interaction/`
   Click `File / Window`, hover `Workspace Tools`, click outside the menu or press `Esc`, trigger a menu command, inspect `Open Root / Popup Chain / Submenu Path / Result / Active Panel / Visible Panels`, press `Reset`, `Capture`, or `F12`.
 
+- `shell/dock_host_basic/`
+  Drag `root-split`, click `Document A`, close `Document B`, click `Details`, close `Console`, inspect `Hover / Result / Active Panel / Visible Panels / Capture / split ratio`, press `Reset`, `Capture`, or `F12`.
+
 - `shell/menu_bar_basic/`
   Click `File / Window / Layout`, move the mouse across menu items, click outside the menu or press `Esc`, press `F12`.