Trim main task queue, recording label, and canvas draw callbacks

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. `main.cpp` main-thread queued
+  task state now lives behind a narrow retained helper instead of
+  `RetainedState.main_tasklist` / `main_task_mutex` directly; broader Win32
+  bootstrap/runtime ownership remains.
+- 2026-06-16: `DEBT-0037` was narrowed again. `App::update_rec_frames()` in
+  `src/app.cpp` now delegates recording label refresh through
+  `update_legacy_recording_frame_label(...)` in
+  `src/legacy_recording_services.cpp` instead of building the label directly;
+  retained recording label lookup, encoder-state reads, and MP4 execution
+  remain.
+- 2026-06-16: `DEBT-0036` was narrowed again. `NodeCanvas` non-`draw_merged`
+  per-frame layer draw callback setup now routes through
+  `make_legacy_canvas_draw_merge_layer_frame_draw(...)` in
+  `src/legacy_canvas_draw_merge_services.h` instead of keeping that callback
+  body inline in `NodeCanvas::draw()`; broader canvas draw orchestration and
+  retained GL resource ownership remain.
 - 2026-06-16: `DEBT-0003` was narrowed again. The Win32 async GL/context lock
   state now lives in `src/platform_windows/windows_platform_services.cpp`
   instead of `src/main.cpp` retained state, and `main.cpp` only seeds the

docs/modernization/roadmap.md

@@ -117,9 +117,10 @@ Current architecture mismatches that must be treated as real blockers:
   checkerboard background setup now route through retained draw-merge helpers,
   with the cache-to-screen checkerboard-plane callback setup also reduced and
   the merged-path checkerboard background-plane callback plus per-plane
-  merged-texture draw callback plus the smoothing-mask face shader/draw pass
-  plus heightmap, current-mode, and grid-mode callback setup now routed
-  through the same retained helper family.
+  merged-texture draw callback plus non-`draw_merged` per-frame layer draw
+  callback plus the smoothing-mask face shader/draw pass plus heightmap,
+  current-mode, and grid-mode callback setup now routed through the same
+  retained helper family.
 - `app_layout.cpp` and `app_dialogs.cpp` are still mixed shell/controller files
   rather than thin composition/binding surfaces.
 - `App`, `Canvas`, `Node`, retained workers, and platform entrypoints still use
@@ -137,13 +138,17 @@ Current architecture mismatches that must be treated as real blockers:
   retained local state object instead of separate process-wide globals, the
   Win32 async GL/context lock state now lives under
   `src/platform_windows/windows_platform_services.cpp` instead of `main.cpp`
-  retained state, the canvas async worker now sits behind a named retained
+  retained state, the main-thread queued task state now sits behind a narrow
+  retained helper instead of `RetainedState.main_tasklist` /
+  `main_task_mutex`, the canvas async worker now sits behind a named retained
   local worker-state helper instead of a bare static accessor, the
   prepared-file worker and the canvas async import/export/save/open worker now
   live under `AppRuntime` instead of retained static app-events/canvas
-  workers, and `App::rec_loop()` now delegates worker-iteration orchestration
-  into the retained recording bridge even though that retained recording path
-  still owns the worker-side readback flow.
+  workers, `App::rec_loop()` now delegates worker-iteration orchestration into
+  the retained recording bridge, and `App::update_rec_frames()` now delegates
+  recording label refresh through that same retained recording path even though
+  the bridge still owns worker-side readback flow and encoder-state label
+  reads.
 - Modern C++23 usage exists in extracted components, especially `std::span`,
   explicit result/status objects, and a few concepts, but the live app still
   does not consistently express ownership, thread affinity, or renderer

docs/modernization/tasks.md

@@ -159,6 +159,10 @@ Current slice:
   also routes through `make_legacy_canvas_draw_merge_layer_texture_draw(...)`,
   but the node still owns broader live layer traversal and renderer-state
   sequencing.
+- `NodeCanvas` non-`draw_merged` per-frame layer draw callback setup now also
+  routes through `make_legacy_canvas_draw_merge_layer_frame_draw(...)`, but
+  the node still owns broader live layer traversal and renderer-state
+  sequencing.
 - `NodeCanvas` smoothing-mask face shader setup plus per-face draw execution
   now also route through
   `execute_legacy_canvas_draw_merge_smask_faces(...)`, but the node still owns
@@ -364,6 +368,8 @@ Current slice:
   `src/platform_windows/windows_platform_services.cpp` instead of `main.cpp`
   retained state, and `main.cpp` only seeds that platform-owned context handle
   pair during initialization and context recreation
+- `main.cpp` main-thread queued task state now sits behind a narrow retained
+  helper instead of `RetainedState.main_tasklist` / `main_task_mutex` directly
 - prepared-file background work now runs through an `AppRuntime`-owned worker
   queue instead of a retained static worker in `src/app_events.cpp`
 - canvas async import/export/save/open background work now also runs through an
@@ -436,6 +442,9 @@ Current slice:
   retained recording bridge in `src/legacy_recording_services.cpp`, while
   `App::update()` no longer carries the dead update mutex residue; retained
   recording loop control, readback ownership, and MP4 execution are still open
+- `App::update_rec_frames()` now delegates recording label refresh through
+  `src/legacy_recording_services.cpp`, but retained recording label lookup,
+  encoder-state reads, and MP4 execution still stay on the legacy bridge
 
 Write scope:
 - `src/canvas.cpp`