Build XCEditor viewport slot shell foundation

tests/UI/Editor/integration/README.md

@@ -18,6 +18,7 @@ Layout:
 - `shell/panel_frame_basic/`: panel frame layout/state/hit-test only
 - `shell/status_bar_basic/`: status bar slot/segment/hit-test only
 - `shell/tab_strip_basic/`: tab strip layout/state/hit-test/close/navigation only
+- `shell/viewport_slot_basic/`: viewport shell chrome/surface/status only
 - `state/panel_session_flow/`: panel session state flow only
 - `state/layout_persistence/`: layout save/load/reset only
 - `state/shortcut_dispatch/`: shortcut match/suppression/dispatch only
@@ -54,6 +55,11 @@ Scenarios:
   Executable: `XCUIEditorTabStripBasicValidation.exe`
   Scope: tab header layout, selected/hover/focus, close hit target, close fallback, Left/Right/Home/End navigation only
 
+- `editor.shell.viewport_slot_basic`
+  Build target: `editor_ui_viewport_slot_basic_validation`
+  Executable: `XCUIEditorViewportSlotBasicValidation.exe`
+  Scope: viewport top bar / surface / status bar layout, hover/focus/active/capture, texture vs fallback only
+
 - `editor.state.panel_session_flow`
   Build target: `editor_ui_panel_session_flow_validation`
   Executable: `XCUIEditorPanelSessionFlowValidation.exe`
@@ -100,6 +106,9 @@ Selected controls:
 - `shell/tab_strip_basic/`
   Click `Document A / B / C`, click `X` on closable tabs, click content to focus, press `Left / Right / Home / End`, press `Reset`, press `F12`.
 
+- `shell/viewport_slot_basic/`
+  Hover toolbar / surface / status bar, click surface to focus, hold and release left mouse to inspect capture, toggle `TopBar / 状态条 / Texture / 方形比例`, press `F12`.
+
 - `state/panel_session_flow/`
   Click `Hide Active / Show Doc A / Close Doc B / Open Doc B / Activate Details / Reset`, press `F12`.