Share retained stroke temporary composite helper

docs/modernization/tasks.md

@@ -509,6 +509,13 @@ Done Checks:
 
 Progress Notes:
 
+- 2026-06-13: `Canvas::draw_merge()` non-erase live temporary-stroke
+  composite ordering now routes through
+  `execute_legacy_canvas_stroke_temporary_composite(...)`; erase-path and
+  broader final composite ownership still remain local to `Canvas`. Next slice
+  should target the erase temporary composite branch or another similarly
+  narrow final composite seam without reopening landed sample, mix, dirty, or
+  framebuffer helpers.
 - 2026-06-13: `Canvas::stroke_draw_samples()` now routes face-indexed
   destination bind/copy/unbind and brush upload/draw through
   `execute_legacy_canvas_stroke_face_sample_polygon(...)`; the retained sample