diff --git a/docs/modernization/build-inventory.md b/docs/modernization/build-inventory.md
index dc55bfc..deed40e 100644
--- a/docs/modernization/build-inventory.md
+++ b/docs/modernization/build-inventory.md
@@ -230,8 +230,9 @@ Known local toolchain state:
 - `src/legacy_grid_ui_services.*` is the current UI-shell bridge for grid
   heightmap picker/load/reload/clear, lightmap render, and heightmap commit
   execution. It keeps those live paths on the `pp_app_core` contracts while
-  legacy image loading, OpenGL texture updates, nanort baking/progress, and
-  `Canvas::draw_objects` execution remain tracked by `DEBT-0024`.
+  legacy image loading, OpenGL texture updates, shared `parallel_for` CPU
+  lightmap baking/progress, and `Canvas::draw_objects` execution remain tracked
+  by `DEBT-0024`.
 - `src/legacy_quick_ui_services.*` is the current UI-shell bridge for quick
   brush/color slot selection, popup routing, mini-state restore, and mini-state
   reset execution. It keeps those live paths on the `pp_app_core` contracts
@@ -351,7 +352,8 @@ Known local toolchain state:
   `NodePanelGrid` heightmap preview and lightmap baking also consume
   backend-owned texture readback formats, sampler filters, depth/blend state,
   depth clears, viewport queries, color-mask booleans, active texture units,
-  and float render-target formats.
+  and float render-target formats; CPU lightmap row dispatch now uses shared
+  `parallel_for` instead of platform-specific worker APIs.
   Legacy `util.cpp` OpenGL error naming and `gl_state` save/restore also
   consume backend-owned error codes, state queries, framebuffer targets,
   texture binding targets, and active texture units.
diff --git a/docs/modernization/debt.md b/docs/modernization/debt.md
index 09925ae..c3e9de6 100644
--- a/docs/modernization/debt.md
+++ b/docs/modernization/debt.md
@@ -41,7 +41,7 @@ agent or engineer to remove them without reconstructing context from chat.
 | DEBT-0021 | Open | Modernization | Layer rename planning/execution dispatch and layer panel operation planning/execution dispatch now consume pure `pp_app_core` through `App::dialog_layer_rename`, `App::init_sidebar` layer callbacks, `pano_cli plan-layer-rename`, `pano_cli plan-layer-operation`, `DocumentLayerRenameServices`, and `DocumentLayerOperationServices`, and the live execution adapters are centralized in `src/legacy_document_layer_services.*`, but that shared bridge still mutates legacy `Canvas` layer state, `NodeLayer`/`NodePanelLayer`, and `ActionManager` undo entries | Preserve existing UI/canvas behavior while document layer commands and undo history are extracted incrementally | `pp_app_core_document_layer_tests`; `pano_cli plan-layer-rename --old-name Base --new-name Paint`; `pano_cli plan-layer-operation --kind add --layer-count 2 --index 1 --name Paint`; `ctest --preset desktop-fast --build-config Debug` | Layer command execution is owned by the document/app command boundary with legacy `Canvas`/UI nodes acting only as adapters or removed entirely |
 | DEBT-0022 | Open | Modernization | Animation panel frame command planning, panel action planning, panel-control/timeline execution dispatch, selected-frame click dispatch, playback tick stepping, and play-mode toggles now consume pure `pp_app_core` through `NodePanelAnimation`, `pano_cli plan-animation-operation`, `pano_cli plan-animation-panel-action`, and `DocumentAnimationServices`; live execution is centralized in `src/legacy_document_animation_services.*`, but that bridge still mutates or reads legacy `Canvas`/`Layer` frame state, canvas mode, animation-panel timeline/playback fields, and uses a temporary `NodePanelAnimation` friend adapter | Preserve existing animation panel behavior while timeline/frame commands move toward the document/app command boundary | `pp_app_core_document_animation_tests`; `pano_cli plan-animation-operation --kind add --frame-count 2 --current-frame 0`; `pano_cli plan-animation-operation --kind select --frame-count 3 --selected-frame 1 --layer-index 2 --layer-id 42`; `pano_cli plan-animation-operation --kind playback --total-duration 5 --current-frame 4 --offset 1`; `pano_cli plan-animation-operation --kind toggle-playback --playing`; `pano_cli plan-animation-panel-action --action next --total-duration 5 --current-frame 4`; `ctest --preset desktop-fast --build-config Debug` | Animation frame/timeline/playback execution is owned by injected document/app timeline services with no legacy `Canvas`/`Layer`/canvas-mode adapter and UI nodes acting only as adapters or removed entirely |
 | DEBT-0023 | Open | Modernization | Brush/color/preset/stroke-settings UI planning, texture-list add/remove/reorder planning, brush preset-list add/select/move/remove/clear planning, stroke-panel slider/toggle/blend/reset planning, and execution dispatch now consume pure `pp_app_core` through `App::init_sidebar`, `NodePanelBrush`, `NodePanelBrushPreset`, `NodePanelStroke`, restored/docked floating-panel callbacks, `pano_cli plan-brush-operation`, `pano_cli plan-brush-texture-list`, `pano_cli plan-brush-preset-list`, `pano_cli plan-brush-stroke-control`, `BrushUiServices`, `BrushTextureListServices`, `BrushPresetListServices`, and `BrushStrokeControlServices`, and live execution is centralized in `src/legacy_brush_ui_services.*` or narrow legacy service bridges where possible, but preset-list execution still mutates legacy `NodePanelBrushPreset` child nodes directly while the bridge still mutates legacy `Brush`/`Canvas::I`, loads/saves legacy brush texture images, refreshes legacy quick/stroke/color widgets, and uses temporary `NodePanelBrush`/`NodePanelBrushPreset` friend adapters to reach private list state | Preserve existing brush UI behavior while brush commands move toward a brush/app/asset command boundary and asset-managed texture/preset selection | `pp_app_core_brush_ui_tests`; `pano_cli plan-brush-operation --kind color --r 0.25 --g 0.5 --b 0.75 --a 1`; `pano_cli plan-brush-operation --kind pattern --path data/patterns/noise.png --thumb data/patterns/thumbs/noise.png`; `pano_cli plan-brush-texture-list --kind add --dir brushes --data-path data --source C:/Temp/soft.png`; `pano_cli plan-brush-preset-list --kind remove --item-count 1 --current-index 0`; `pano_cli plan-brush-stroke-control --kind float --setting tip-size --value 42.5`; `pano_cli plan-brush-stroke-control --kind blend --setting pattern --blend-mode 3`; `ctest --preset desktop-fast --build-config Debug` | Brush color/texture/preset/stroke-settings, texture-list, preset-list, and stroke-control execution are owned by injected brush/app/asset/UI services with no legacy brush/canvas adapter, direct `NodePanelBrushPreset` child mutation, or brush-panel friend access |
-| DEBT-0024 | Open | Modernization | Grid/heightmap/lightmap UI planning and execution dispatch now consume pure `pp_app_core` through `NodePanelGrid`, `pano_cli plan-grid-operation`, and the `GridUiServices` boundary; live execution is centralized in `src/legacy_grid_ui_services.*`, but the bridge still performs legacy image loading, OpenGL texture updates, nanort lightmap baking/progress, and `Canvas::draw_objects` commit execution | Preserve grid/lightmap behavior while moving renderable grid commands toward app/renderer/document boundaries | `pp_app_core_grid_ui_tests`; `pano_cli plan-grid-operation --kind render --float32 --texture-resolution 1024 --samples 32`; `ctest --preset desktop-fast --build-config Debug` | Grid heightmap/lightmap execution is owned by app/renderer/document services with `NodePanelGrid` acting only as UI adapter |
+| DEBT-0024 | Open | Modernization | Grid/heightmap/lightmap UI planning and execution dispatch now consume pure `pp_app_core` through `NodePanelGrid`, `pano_cli plan-grid-operation`, and the `GridUiServices` boundary; live execution is centralized in `src/legacy_grid_ui_services.*`, and retained CPU lightmap row dispatch now uses shared `parallel_for` instead of platform-specific Win32/Apple worker APIs, but the bridge still performs legacy image loading, OpenGL texture updates, nanort lightmap baking/progress, and `Canvas::draw_objects` commit execution | Preserve grid/lightmap behavior while moving renderable grid commands toward app/renderer/document boundaries | `pp_app_core_grid_ui_tests`; `pano_cli plan-grid-operation --kind render --float32 --texture-resolution 1024 --samples 32`; `ctest --preset desktop-fast --build-config Debug` | Grid heightmap/lightmap execution is owned by app/renderer/document services with `NodePanelGrid` acting only as UI adapter |
 | DEBT-0025 | Open | Modernization | Quick brush/color slot and mini-state planning and execution dispatch now consume pure `pp_app_core` through `NodePanelQuick`, `pano_cli plan-quick-operation`, and the `QuickUiServices` boundary; live execution is centralized in `src/legacy_quick_ui_services.*`, but the bridge still mutates legacy quick UI widgets, `Brush` previews, color picker popup state, and preset popup state | Preserve quick-panel behavior while quick brush/color commands move toward a brush/app command boundary with safer automation coverage | `pp_app_core_quick_ui_tests`; `pano_cli plan-quick-operation --kind brush --current-index 0 --slot-index 2`; `pano_cli plan-quick-operation --kind restore --brush-index 2 --color-index 1 --fire-event`; `ctest --preset desktop-fast --build-config Debug` | Quick-panel selection, popup, restore, reset, brush preview, and color execution are owned by injected app/brush/UI services with no legacy quick-panel adapter |
 | DEBT-0026 | Open | Modernization | Toolbar history command planning and canvas hotkey history dispatch now consume pure `pp_app_core` through `App::init_toolbar_main`, `NodeCanvas`, `pano_cli plan-history-operation`, and the `HistoryUiServices` boundary, and both live callers share `src/legacy_history_services.*` for saturated legacy history metrics and execution, but the shared live bridge still mutates legacy `ActionManager` stacks directly | Preserve undo/redo/clear behavior while moving action history toward document/app command services | `pp_app_core_history_ui_tests`; `pano_cli plan-history-operation --kind undo --undo-count 2`; `pano_cli plan-history-operation --kind clear --undo-count 2 --redo-count 1 --memory-bytes 4096`; `ctest --preset desktop-fast --build-config Debug` | Undo/redo/clear execution is owned by injected document/app history services with no legacy `ActionManager` adapter |
 | DEBT-0027 | Open | Modernization | Canvas draw-tool toolbar command, canvas input mode switching, active-state planning/execution dispatch, and canvas keyboard/touch command planning now consume pure `pp_app_core` through `App::init_toolbar_draw`, `App::update`, `NodeCanvas`, `pano_cli plan-canvas-tool`, `pano_cli plan-canvas-tool-state`, `pano_cli plan-canvas-hotkey`, `CanvasToolServices`, and `CanvasHotkeyServices`, and live toolbar/input/hotkey execution is centralized in `src/legacy_canvas_tool_services.*`, but the bridge still mutates or reads legacy `Canvas` mode state, pen picking state, touch-lock state, transform copy/cut action objects, `ActionManager`, legacy save UI, legacy stroke size controls, and cursor/UI singletons | Preserve current toolbar, stylus eraser, keyboard, and touch command behavior while canvas input/tools move toward an app/document command boundary | `pp_app_core_canvas_tool_ui_tests`; `pp_app_core_canvas_hotkey_tests`; `pano_cli plan-canvas-tool --kind copy`; `pano_cli plan-canvas-tool-state --mode draw --picking --touch-lock`; `pano_cli plan-canvas-hotkey --event key-up --key z --ctrl --undo-count 2`; `pano_cli plan-canvas-hotkey --event key-up --key s --ctrl --shift`; `ctest --preset desktop-fast --build-config Debug` | Canvas tool selection, toolbar state refresh, picking, touch lock, stylus eraser/key mode switching, hotkey/touch command dispatch, save hotkeys, history hotkeys, brush-size hotkeys, and transform action execution are owned by injected app/document/canvas services with no legacy toolbar/canvas adapter |
diff --git a/docs/modernization/roadmap.md b/docs/modernization/roadmap.md
index 7931864..ab274a5 100644
--- a/docs/modernization/roadmap.md
+++ b/docs/modernization/roadmap.md
@@ -588,6 +588,10 @@ commit used by the live grid panel. Grid execution now dispatches through
 `GridUiServices` in `src/legacy_grid_ui_services.*` before legacy image loading,
 OpenGL texture updates, nanort lightmap baking, and `Canvas::draw_objects`
 execution continue.
+The retained `NodePanelGrid` lightmap bake now uses the shared `parallel_for`
+helper instead of platform-specific Win32 Concurrency Runtime and Apple
+`dispatch_apply` branches, keeping the row-dispatch policy in common legacy
+infrastructure while the bake itself remains debt-tracked.
 `pano_cli plan-history-operation` exposes app-core planning for undo, redo, and
 clear-history availability used by toolbar buttons and canvas shortcuts; live
 toolbar and canvas-hotkey execution now dispatch through a shared app-shell
@@ -1005,7 +1009,8 @@ and RGBA8 read/write pixel mapping to `pp_renderer_gl`.
 `NodePanelGrid` heightmap preview and lightmap baking now delegate texture
 readback formats, sampler filters, depth/blend state, depth clears, viewport
 queries, color-mask booleans, active texture units, and float render-target
-formats to `pp_renderer_gl`.
+formats to `pp_renderer_gl`, and its CPU lightmap row dispatch now uses the
+shared legacy `parallel_for` helper rather than platform-specific worker APIs.
 Legacy `util.cpp` OpenGL error naming and `gl_state` save/restore now delegate
 error codes, state queries, framebuffer targets, texture binding targets, and
 active texture units to `pp_renderer_gl`.
diff --git a/src/node_panel_grid.cpp b/src/node_panel_grid.cpp
index b007312..8749754 100644
--- a/src/node_panel_grid.cpp
+++ b/src/node_panel_grid.cpp
@@ -419,17 +419,10 @@ void NodePanelGrid::bake_uvs()
     std::thread worker([&]
     {
         BT_SetTerminate();
-        __block float* d_pos = data_pos.get();
-        __block float* d_nor = data_nor.get();
-        __block glm::u8vec4* d_out = reinterpret_cast<glm::u8vec4*>(data_out.get());
-#if _WIN32
-        concurrency::parallel_for(int(0), fb.getHeight(), [&](int y)
-#elif __IOS__ || __OSX__
-        dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
-        dispatch_apply((size_t)fb.getHeight(), queue, ^ (size_t y)
-#else
-        parallel_for(fb.getHeight(), [&](int y)
-#endif
+        float* d_pos = data_pos.get();
+        float* d_nor = data_nor.get();
+        auto* d_out = reinterpret_cast<glm::u8vec4*>(data_out.get());
+        parallel_for(fb.getHeight(), [&](size_t y)
         {
             for (int x = 0; x < fb.getWidth(); x++)
             {