Extract sidebar, lifecycle shell, and canvas unmerged draw

docs/modernization/tasks.md

@@ -210,6 +210,11 @@ Current slice:
   `execute_node_canvas_draw_merge_tail(...)`, which trims another live tail
   block from `NodeCanvas::draw()` even though the broader outer draw shell is
   still inline.
+- `NodeCanvas` non-`draw_merged` cache/background/layer-traversal/cache-
+  composite shell now also routes through
+  `execute_legacy_canvas_draw_unmerged_shell(...)`, which removes another
+  coherent orchestration block from `NodeCanvas::draw()` even though the
+  broader node draw loop still lives in `src/node_canvas.cpp`.
 
 Write scope:
 - `src/node_stroke_preview.cpp`
@@ -304,6 +309,10 @@ Current slice:
   `src/app_layout_about_layer_menu.cpp`, and `App::init_menu_about()` plus
   `App::init_menu_layer()` are now thin call-throughs, but edit/sidebar and
   broader layout composition are still inline in `src/app_layout.cpp`.
+- Sidebar panel binding plus popup wiring now also live in
+  `src/app_layout_sidebar.cpp`, and `App::init_sidebar()` is now a thin
+  call-through, but edit-menu wiring and broader layout composition are still
+  inline in `src/app_layout.cpp`.
 
 Write scope:
 - `src/app_layout.cpp`
@@ -460,6 +469,10 @@ Current slice:
   conversion, `UnadjustWindowRectEx`, and GL debug pre/post callbacks now also
   live in `src/platform_windows/windows_bootstrap_helpers.cpp` instead of
   `src/main.cpp`
+- Win32 lifecycle running-state, close/shutdown handling, FPS title update and
+  wakeup posting, stylus frame update, window preference save, and VR
+  lifecycle wrappers now also live in
+  `src/platform_windows/windows_lifecycle_shell.cpp` instead of `src/main.cpp`
 - 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