Extract legacy platform services adapter

docs/modernization/roadmap.md

@@ -474,8 +474,8 @@ display, file sharing, image/file/save-file pickers, and directory pickers.
 Windows installs an injected `WindowsPlatformServices` implementation from
 `src/platform_windows/windows_platform_services.*` in `pp_platform_windows`;
 other platforms still route through the debt-tracked legacy fallback adapter
-in `app_events.cpp`, so behavior is preserved while their platform shell
-implementations are extracted. The iOS/Web
+now isolated in `src/platform_legacy/legacy_platform_services.*`, so behavior
+is preserved while their platform shell implementations are extracted. The iOS/Web
 save-with-writer overload remains separate because it writes a
 temporary/exported file before handing control to the platform.
 `pano_cli plan-cloud-upload` exposes the app-core cloud upload decision used by
@@ -995,7 +995,9 @@ Results:
   live Windows app now consumes this interface through an injected
   `WindowsPlatformServices` instance isolated in
   `src/platform_windows/windows_platform_services.*`; other platforms still
-  use the legacy fallback adapter.
+  use the legacy fallback adapter, now isolated in
+  `src/platform_legacy/legacy_platform_services.*` instead of being owned by
+  `app_events.cpp`.
 - `panopainter_validate_shaders` passed, validating 25 shader programs and 7
   shader includes for stage markers and include graph integrity.
 - `pp_renderer_gl_capabilities_tests` passed on default MSVC, vcpkg-headless,