Record STR-051 closeout hash

docs/modernization/debt.md

@@ -18,6 +18,12 @@ agent or engineer to remove them without reconstructing context from chat.
 
 ## Recent Reductions
 
+- 2026-06-14: `DEBT-0036` was narrowed again. `execute_canvas_draw_merge_branch_body()`
+  now routes the temporary erase, texture, and blend dispatch bodies through
+  `make_canvas_draw_merge_temporary_erase_dispatch(...)`,
+  `make_canvas_draw_merge_layer_texture_dispatch(...)`, and
+  `make_canvas_draw_merge_layer_blend_dispatch(...)`; the branch body still
+  owns the selection guard and execution dispatch.
 - 2026-06-14: `DEBT-0036` was narrowed again. `Canvas::draw_merge_temporary_paint_branch()`
   now routes the retained temporary-paint request construction through
   `make_canvas_draw_merge_temporary_paint_request(...)`; the temporary-paint