Add CMake vcpkg UI validation target

docs/modernization/build-inventory.md

@@ -71,6 +71,7 @@ $env:VCPKG_ROOT = "C:\Program Files\Microsoft Visual Studio\2022\Community\VC\vc
 cmake --preset windows-msvc-vcpkg-headless
 powershell -ExecutionPolicy Bypass -File scripts\automation\platform-build.ps1 -Presets windows-msvc-vcpkg-headless
 ctest --preset desktop-fast-vcpkg --build-config Debug
+cmake --build --preset windows-msvc-default --config Debug --target panopainter_platform_build_vcpkg_ui_core
 cmake --preset android-arm64
 powershell -ExecutionPolicy Bypass -File scripts\automation\platform-build.ps1 -Presets android-arm64
 powershell -ExecutionPolicy Bypass -File scripts\automation\android-legacy-package-build.ps1 -Packages standard
@@ -99,6 +100,10 @@ Known local toolchain state:
 - Local Visual Studio generator selected by CMake: Visual Studio 17 2022
 - Bundled vcpkg: `C:\Program Files\Microsoft Visual Studio\2022\Community\VC\vcpkg`
   (`vcpkg version` reports 2025-11-19)
+- External vcpkg: `D:\vcpkg` is currently resolved by
+  `scripts/automation/platform-build.ps1` when `VCPKG_ROOT` is already set on
+  this host; the wrapper falls back to bundled Visual Studio vcpkg roots when
+  needed.
 - Android SDK: `C:\Users\omara\AppData\Local\Android\Sdk`
 - Android NDK: latest SDK Manager package selected by
   `scripts/automation/android-sdk-env.ps1`; currently
@@ -200,7 +205,8 @@ powershell -ExecutionPolicy Bypass -File scripts\automation\apple-remote-build.p
   root CMake package targets yet.
 - Root CMake exposes non-default platform validation targets:
   `panopainter_platform_build_headless`,
-  `panopainter_platform_build_android_assets`, and
+  `panopainter_platform_build_android_assets`,
+  `panopainter_platform_build_vcpkg_ui_core`, and
   `panopainter_platform_build_apple_remote`. These targets call the existing
   platform automation scripts from CMake and keep platform validation discoverable
   from the CMake target graph while app/package target migration remains open.
@@ -610,7 +616,9 @@ powershell -ExecutionPolicy Bypass -File scripts\automation\apple-remote-build.p
   of owning active WGL context/pixel-format attribute literals in `main.cpp`.
 - `windows-msvc-vcpkg-headless` validates manifest install/configure/build/test
   for the current headless component matrix; see DEBT-0007 for remaining app
-  and platform triplet migration.
+  and platform triplet migration. Root CMake target
+  `panopainter_platform_build_vcpkg_ui_core` focuses that gate on the
+  vcpkg-backed `pp_ui_core`/tinyxml2 boundary and `pp_ui_core_layout_xml_tests`.
 - `scripts/automation/analyze.*` runs shader validation plus a
   renderer-boundary guard that reports JSON and fails if active non-backend
   source code reintroduces raw `GL_*`/`WGL_*` constants outside the allowed

docs/modernization/roadmap.md

@@ -298,7 +298,11 @@ exist. `windows-clangcl-asan` now configures as a headless Ninja/clang-cl ASan
 preset and uses the release MSVC runtime required by clang-cl ASan, but local
 ASan builds are blocked by DEBT-0014 until Clang and the selected MSVC STL are
 compatible. Dependency migration is not complete until remaining component
-dependencies and mobile/Apple triplets are validated.
+dependencies and mobile/Apple triplets are validated. Root CMake now also
+exposes `panopainter_platform_build_vcpkg_ui_core`, a focused automation target
+that resolves `VCPKG_ROOT` through the platform-build wrapper and validates the
+vcpkg-backed `pp_ui_core`/tinyxml2 XML test boundary from the CMake target
+graph.
 
 Implementation tasks:
 
@@ -1386,7 +1390,8 @@ Focus/Wave arm64. The shell wrapper now mirrors the PowerShell wrapper's
 multi-preset behavior and reports one structured result array. Root CMake now
 also exposes non-default platform validation targets:
 `panopainter_platform_build_headless`,
-`panopainter_platform_build_android_assets`, and
+`panopainter_platform_build_android_assets`,
+`panopainter_platform_build_vcpkg_ui_core`, and
 `panopainter_platform_build_apple_remote`; the platform-build self-test guards
 those target names and the wrapper matrix now includes
 `pp_app_core_app_dialog_tests` with the rest of the CMake test executables.
@@ -2408,11 +2413,14 @@ Results:
   still-blocked Windows AppX package state.
 - Root CMake now exposes platform validation targets for the default headless
   platform-build sweep, the Android standard/Quest/Focus root CMake asset
-  component sweep, and the remote Apple compile gate. `cmake --build --preset
+  component sweep, the vcpkg-backed UI core dependency boundary, and the
+  remote Apple compile gate. `cmake --build --preset windows-msvc-default
+  --config Debug --target panopainter_platform_build_android_assets` validated
+  `pp_assets` across Android arm64, Android x64, Quest arm64, and Focus/Wave
+  arm64 with the latest SDK-managed NDK/CMake pair; `cmake --build --preset
   windows-msvc-default --config Debug --target
-  panopainter_platform_build_android_assets` validated `pp_assets` across
-  Android arm64, Android x64, Quest arm64, and Focus/Wave arm64 with the latest
-  SDK-managed NDK/CMake pair.
+  panopainter_platform_build_vcpkg_ui_core` validated `pp_ui_core` and
+  `pp_ui_core_layout_xml_tests` through the vcpkg tinyxml2 preset.
 - Desktop VR drawing now routes generic OpenGL scissor/depth/blend state,
   blend/depth state snapshots and restores, depth clears, active texture units,
   and fallback 2D texture unbinds through tested renderer GL backend dispatch;