Add retained stroke execution helper tests

docs/modernization/roadmap.md

@@ -3123,6 +3123,10 @@ Results:
   texture-input dispatch now shares retained stroke execution helpers, while
   concrete GL object mapping, framebuffer ownership, shader timing, and final
   draw execution remain in the legacy Canvas path.
+- `pp_paint_renderer_stroke_execution_tests` now covers retained stroke texture
+  input binding order, sample execution destination-copy behavior, live-pass
+  face-framebuffer dirty tracking, and pad-face destination-copy behavior
+  without depending on the broader compositor test translation unit.
 - `Canvas::stroke_draw` pad-pass destination bind/copy/unbind ordering now
   shares the retained stroke execution helper callback surface, while shader
   setup, pad color selection, framebuffer ownership, and final OpenGL draw