Expose Linux WebGL package readiness target

docs/modernization/roadmap.md

@@ -1410,9 +1410,11 @@ checks: `panopainter_package_readiness`,
 `panopainter_windows_app_package_smoke`,
 `panopainter_android_standard_native_package`,
 `panopainter_android_vr_native_package_configure`, and
-`panopainter_android_native_package_smoke`. App/package entrypoints still need
-to consume shared targets and remain covered by debt until package validation
-is migrated from legacy package projects to root CMake.
+`panopainter_android_native_package_smoke`, plus the retained Linux/WebGL
+blocker target `panopainter_linux_webgl_package_readiness`. App/package
+entrypoints still need to consume shared targets and remain covered by debt
+until package validation is migrated from legacy package projects to root
+CMake.
 Retained Linux and WebGL app CMake entrypoints now match the interim platform
 baseline used by Android package paths: CMake 3.10 plus target-level
 `cxx_std_23`, with `panopainter_retained_platform_cmake_self_test` guarding
@@ -2394,7 +2396,9 @@ Results:
   targets are migrated to root CMake. Readiness-only mode now reports the same
   matrix without building the app first, and the package readiness self-test
   keeps wrapper package kinds, retained Linux/WebGL CMake metadata, and blocker
-  metadata aligned.
+  metadata aligned. Root CMake target
+  `panopainter_linux_webgl_package_readiness` now exposes the filtered retained
+  Linux/WebGL readiness matrix from the CMake target graph.
 - Android standard arm64/x64, Quest arm64, and Focus/Wave arm64 configure
   through the platform-build wrapper by default. Focused validation compiled
   representative headless component/tool targets across all four presets, and