Use Android platform services in retained package builds

docs/modernization/roadmap.md

@@ -70,6 +70,16 @@ What is already real:
 - `pp_app_core`
 
 Latest slice:
+- `android/android/CMakeLists.txt`, `android/quest/CMakeLists.txt`, and
+  `android/focus/CMakeLists.txt` now compile
+  `src/platform_android/android_platform_services.cpp` instead of
+  `src/platform_legacy/legacy_platform_services.cpp`.
+- The retained Android package graphs now match `android/src/cpp/main.cpp`,
+  which already constructs concrete Android `PlatformServices` directly.
+- The retained standard Android package link gate still fails after this slice,
+  but it also fails after restoring the old legacy source list, so the current
+  retained-package linker break remains preexisting and outside the behavior
+  change of this swap.
 - `cmake/PanoPainterSources.cmake` no longer adds
   `src/platform_legacy/legacy_platform_services.*` to
   `PP_PANOPAINTER_APP_SOURCES`, so the root `panopainter_app` target graph