Promote stroke commit history mutation task

docs/modernization/tasks.md

@@ -1837,6 +1837,35 @@ ctest --preset desktop-fast --build-config Debug -R "pp_paint_renderer_stroke_ex
 & 'C:\Program Files\Microsoft Visual Studio\18\Community\MSBuild\Current\Bin\MSBuild.exe' out\build\windows-msvc-default\tests\pp_paint_renderer_stroke_execution_tests.vcxproj /p:Configuration=Debug /p:Platform=x64
 ```
 
+### STR-040 - Extract Stroke Commit Local History And Dirty Mutation
+
+Status: Ready
+Score: +1 renderer boundary and OpenGL parity
+Debt: `DEBT-0036`
+Scope: `src/canvas.cpp`, `tests/paint_renderer/stroke_execution_tests.cpp`
+
+Goal:
+
+Move the remaining local history and dirty-mutation work inside
+`make_canvas_stroke_commit_callbacks()` into a retained helper so the callback
+builder only forwards concrete canvas state.
+
+Done Checks:
+
+- `make_canvas_stroke_commit_callbacks()` no longer owns the history/dirty
+  mutation block inline.
+- Regression coverage proves the helper preserves action bookkeeping and dirty
+  box updates.
+- `docs/modernization/debt.md` records the reduced stroke-commit history
+  surface.
+
+Validation:
+
+```powershell
+ctest --preset desktop-fast --build-config Debug -R "pp_paint_renderer_stroke_execution" --output-onfailure
+& 'C:\Program Files\Microsoft Visual Studio\18\Community\MSBuild\Current\Bin\MSBuild.exe' out\build\windows-msvc-default\tests\pp_paint_renderer_stroke_execution_tests.vcxproj /p:Configuration=Debug /p:Platform=x64
+```
+
 ### STR-010 - Extract Remaining Draw Merge Composite Orchestration
 
 ### STR-016 - Extract Draw Merge Layer Composite Execution