Extend retained stroke frame sample tests

docs/modernization/tasks.md

@@ -509,6 +509,13 @@ Done Checks:
 
 Progress Notes:
 
+- 2026-06-13: `pp_paint_renderer_stroke_execution_tests` now also covers
+  direct retained frame-sample callback ordering plus
+  `execute_legacy_canvas_stroke_frame_samples_with_dirty_tracking(...)`
+  timing/state semantics, including pre-update dirty visibility and
+  `previous_pass_dirty_box` override behavior. Next test slice should target
+  the next header-level preview live sample ordering surface without reopening
+  production files.
 - 2026-06-13: `Canvas::stroke_draw_mix()` now routes visible-plane filtering,
   retained sampler/texture-slot binding, and final plane draw ordering through
   `execute_legacy_canvas_stroke_mix_pass(...)`; mixer framebuffer/state setup