Record STR-031 closeout hash

docs/modernization/debt.md

@@ -282,6 +282,10 @@ agent or engineer to remove them without reconstructing context from chat.
   callback body now routes through `stroke_draw_pad_face_callback_body(...)`;
   the retained path still owns the concrete pad shader setup, face selection,
   and copy wiring.
+- 2026-06-13: DEBT-0036 was narrowed again. `Canvas::draw_merge()` temporary
+  paint branch now routes through `draw_merge_temporary_paint_branch(...)`;
+  the retained path still owns the concrete temporary-paint setup, texture
+  binding, and draw ordering.
 - 2026-06-13: DEBT-0036 was narrowed again. `Canvas::stroke_draw()` main-pass
   live face orchestration now routes through
   `execute_legacy_canvas_stroke_live_pass_with_face_framebuffers(...)`; the