Promote stroke draw samples callback task

docs/modernization/tasks.md

@@ -1954,6 +1954,34 @@ Validation:
 ctest --preset desktop-fast --build-config Debug -R "pp_paint_renderer_stroke_execution" --output-onfailure
 ```
 
+### STR-035 - Extract Stroke Draw Samples Callback Body
+
+Status: Ready
+Score: +1 renderer boundary and OpenGL parity
+Debt: `DEBT-0036`
+Scope: `src/canvas.cpp`, `src/legacy_canvas_stroke_execution_services.h`, `tests/paint_renderer/compositor_tests.cpp`
+
+Goal:
+
+Move the remaining `Canvas::stroke_draw_samples()` callback body into a
+retained helper so the callsite keeps only request dispatch and dirty-bounds
+return handling.
+
+Done Checks:
+
+- `Canvas::stroke_draw_samples()` no longer owns the face-sample callback body
+  inline.
+- Regression coverage proves the callback helper preserves destination-copy
+  behavior and brush upload/draw ordering.
+- `docs/modernization/debt.md` records the reduced stroke-sample callback
+  surface.
+
+Validation:
+
+```powershell
+ctest --preset desktop-fast --build-config Debug -R "pp_paint_renderer_stroke_execution" --output-onfailure
+```
+
 ### STR-012 - Extract Preview Final Composite Orchestration
 
 Status: Done