Move prepared-file work into app runtime

docs/modernization/debt.md

@@ -18,6 +18,22 @@ agent or engineer to remove them without reconstructing context from chat.
 
 ## Reductions
 
+- 2026-06-16: `DEBT-0003` was narrowed again. Prepared-file background work
+  now runs through an `AppRuntime`-owned queue/worker in
+  `src/app_runtime.h/.cpp`, and `src/app_events.cpp` no longer defines a
+  retained static prepared-file worker; broader app task ownership and canvas
+  async worker ownership remain.
+- 2026-06-16: `DEBT-0037` was narrowed again. `App::rec_loop()` in
+  `src/app.cpp` now routes its worker-iteration pointer lookup plus
+  `plan_recording_worker_iteration(...)` setup through a local helper instead
+  of carrying that setup inline; retained recording loop control, readback call
+  sites, and MP4 execution remain.
+- 2026-06-16: `DEBT-0036` was narrowed again. `NodeCanvas` current-mode draw
+  callback setup now routes through
+  `make_legacy_canvas_draw_merge_current_modes_draw(...)` in
+  `src/legacy_canvas_draw_merge_services.h` instead of keeping that callback
+  loop inline in `NodeCanvas::draw()`; broader canvas draw orchestration and
+  retained GL resource ownership remain.
 - 2026-06-16: `DEBT-0037` was narrowed again. `App::rec_loop()` in
   `src/app.cpp` now routes its coherent frame encode/update chunk through a
   local helper instead of carrying dirty-stroke clearing, equirect PBO