Reduce draw merge branch dispatch mismatch

docs/modernization/debt.md

@@ -409,6 +409,10 @@ agent or engineer to remove them without reconstructing context from chat.
   now drops the unused `draw_checkerboard` parameter from the temporary-paint
   wrapper, shrinking the remaining draw-merge helper mismatch while the
   blocked extraction still stays in `STR-016`.
+- 2026-06-15: `DEBT-0036` was narrowed again. The stale
+  `make_canvas_draw_merge_branch_dispatch(...)` forward declaration in
+  `src/canvas.cpp` now matches the 7-argument implementation, shrinking the
+  remaining draw-merge helper API mismatch while `STR-016` stays blocked.
 - 2026-06-14: `DEBT-0036` was narrowed again. `Canvas::draw_merge_branch_orchestration()`
   now routes the temporary erase, temporary paint, texture, and blend dispatch
   bodies through retained helpers inside `execute_canvas_draw_merge_branch_body(...)`;