Thin recording bridge and canvas draw seams

docs/modernization/debt.md

@@ -18,6 +18,18 @@ agent or engineer to remove them without reconstructing context from chat.
 
 ## Reductions
 
+- 2026-06-16: `DEBT-0037` was narrowed again. `App::rec_loop()` in
+  `src/app.cpp` now delegates recording worker iteration orchestration into
+  `process_legacy_recording_worker_iteration(...)` in
+  `src/legacy_recording_services.cpp` instead of owning the wait/plan/encode
+  shell itself; retained recording loop control, readback call sites, and MP4
+  execution remain.
+- 2026-06-16: `DEBT-0036` was narrowed again. `NodeCanvas` checkerboard
+  background-plane callback setup now routes through
+  `make_legacy_canvas_draw_merge_background_checkerboard_plane(...)` in
+  `src/legacy_canvas_draw_merge_services.h` instead of keeping that callback
+  inline in `NodeCanvas::draw()`; broader canvas draw orchestration and
+  retained GL resource ownership remain.
 - 2026-06-16: `DEBT-0003` was narrowed again. Canvas async
   import/export/save/open background work now runs through an
   `AppRuntime`-owned queue/worker in `src/app_runtime.h/.cpp`, and