Split asset reload platform policy

docs/modernization/debt.md

@@ -235,6 +235,13 @@ agent or engineer to remove them without reconstructing context from chat.
   policy, and canvas tip visibility.
   `WindowsPlatformServices` and the non-Windows legacy fallback consume those
   helpers while SDK-specific execution remains open in platform shells.
+- 2026-06-05: DEBT-0054 was narrowed. Layout XML file reload policy now has a
+  pure `plan_asset_file_load_with_probe` decision in `pp_platform_api`, with
+  Windows/macOS mtime reload behavior and mobile/Web already-loaded no-op
+  behavior selected by the tested `platform_policy` catalog. The live
+  `plan_asset_file_load` wrapper still performs the retained `stat` probe for
+  mtime platforms until asset/file watching is owned by injected storage
+  services.
 - 2026-06-04: DEBT-0036 was narrowed again. Canvas stroke commit,
   thumbnail, and object-draw history paths now query saved blend state through
   tested `pp_renderer_gl` capability-state dispatch; CanvasLayer equirect
@@ -302,7 +309,7 @@ agent or engineer to remove them without reconstructing context from chat.
 | DEBT-0051 | Open | Modernization | Document browser search roots and Browse dialog working-directory picker visibility/path formatting now dispatch through `PlatformServices`; iOS Inbox roots and working-directory picker availability live in tested `pp_platform_api::platform_policy`, but macOS directory picker/display-path execution still lives in `src/platform_legacy/legacy_platform_services.*` | Preserve current iOS document import/browse and desktop browse picker behavior while Apple platform shells are extracted incrementally | `pp_platform_api_tests`; `ctest --preset desktop-fast --build-config Debug`; Apple package smoke once root Apple builds exist | Document browse roots and browse-directory picker/display formatting are owned by injected Apple and desktop `pp_platform_*` services with no legacy adapter branch |
 | DEBT-0052 | Open | Modernization | Native UI/window state saving now dispatches through `PlatformServices`; Windows/macOS save policy lives in tested `pp_platform_api::platform_policy`, but macOS execution still lives in `src/platform_legacy/legacy_platform_services.*` and forwards to the retained Objective-C app bridge | Preserve current Windows/macOS UI persistence while platform shells are extracted incrementally | `pp_platform_api_tests`; `ctest --preset desktop-fast --build-config Debug`; Windows app build; Apple package smoke once root Apple builds exist | UI/window state persistence is owned by injected platform services with no legacy adapter branch |
 | DEBT-0053 | Open | Modernization | Prepared-file writable target selection and prepared-file export-dialog policy now dispatch through `PlatformServices`; iOS temporary-file and WebGL data-path target planning live in tested `pp_platform_api::platform_policy`, but retained iOS/Web save/download handoff execution still lives in `src/platform_legacy/legacy_platform_services.*` | Preserve mobile/Web export handoff behavior while platform shells are extracted incrementally | `pp_platform_api_tests`; `ctest --preset desktop-fast --build-config Debug`; Windows app build; Apple/Web package smoke once root package builds exist | Prepared-file target selection, export-dialog policy, and save/download handoff are owned by injected platform services with no legacy adapter branch |
-| DEBT-0054 | Open | Modernization | Layout XML file read/reload decisions now consume `pp_platform_api::plan_asset_file_load`, but that helper still encodes the retained compile-time platform policy: Windows/macOS use `stat` mtime reload checks, while other platforms treat already-loaded layouts as successful no-op loads | Preserve current layout hot-reload and mobile/Web single-load behavior while removing platform guards from the shared `LayoutManager` parser | `pp_platform_api_tests`; `ctest --preset desktop-fast --build-config Debug -R pp_platform_api_tests`; Windows app build | Layout reload decisions are owned by injected platform storage/file-watch services or an asset manager boundary with platform-specific file watching removed from compile-time helpers |
+| DEBT-0054 | Open | Modernization | Layout XML file read/reload decisions now consume `pp_platform_api::plan_asset_file_load`; platform-family reload behavior lives in tested `pp_platform_api::platform_policy` and pure probed planning, but the live wrapper still performs direct `stat` probing for Windows/macOS mtime reload checks until platform storage/file-watch services exist | Preserve current layout hot-reload and mobile/Web single-load behavior while removing platform guards from the shared `LayoutManager` parser | `pp_platform_api_tests`; `ctest --preset desktop-fast --build-config Debug -R pp_platform_api_tests`; Windows app build | Layout reload decisions are owned by injected platform storage/file-watch services or an asset manager boundary with platform-specific file watching removed from compile-time helpers |
 | DEBT-0055 | Open | Modernization | `src/app.h` now forward-declares retained iOS/macOS/Android/Linux/Web platform handles instead of including platform SDK headers, and full SDK includes are isolated in `src/platform_legacy/legacy_platform_services.cpp`, but the `App` singleton still stores those platform handles directly | Reduce central header platform coupling incrementally without rewriting non-Windows platform entrypoints before Phase 6 | Windows app build; Apple/Android/Linux/Web package smoke once platform root builds are active | Platform handles are owned by injected `pp_platform_*` shell state or services, and `App` has no platform SDK handle fields or platform conditional members |
 | DEBT-0056 | Open | Modernization | `src/asset.h` now forward-declares Android asset-manager types and uses `Asset::set_android_asset_manager` instead of public mutable manager state, but retained `Asset` still stores Android asset handles and `src/asset.cpp` still performs Android `AAssetManager` reads directly; the current `android-arm64` root preset is headless and does not expose `pp_legacy_assets_io` | Reduce legacy asset I/O header coupling without rewriting Android asset loading before the asset manager/storage boundary exists | Windows app build; `cmake --build --preset android-arm64 --target pp_assets`; Android package smoke once package builds consume shared targets | Android asset loading is owned by injected asset storage/platform services or `pp_assets` file providers, with no static Android asset manager on `Asset` |
 | DEBT-0057 | Open | Modernization | Default canvas allocation size now dispatches through `PlatformServices::default_canvas_resolution`, removing the `CANVAS_RES` platform macro from `src/canvas.h`; WebGL's retained 512 default now lives in tested `pp_platform_api::platform_policy`, but the Web shell still reaches it through the legacy platform fallback until injected Web services own the policy | Preserve WebGL memory behavior while moving canvas creation policy out of shared canvas headers and into the platform boundary | `pp_platform_api_tests`; `ctest --preset desktop-fast --build-config Debug -R pp_platform_api_tests`; Windows app build; WebGL package smoke once root Web build exists | Default canvas resolution is owned by injected `pp_platform_*` services for every supported platform, with no WebGL branch in the legacy fallback |