Thin node loader, Win32 wrappers, and canvas mode shells

docs/modernization/roadmap.md

@@ -81,9 +81,9 @@ Current hotspot files:
 
 - `src/canvas.cpp`: 17 lines
 - `src/app_layout.cpp`: 125 lines
-- `src/canvas_modes.cpp`: 191 lines
-- `src/node.cpp`: 257 lines
-- `src/main.cpp`: 156 lines
+- `src/canvas_modes.cpp`: 1 line
+- `src/node.cpp`: 231 lines
+- `src/main.cpp`: 87 lines
 - `src/node_panel_brush.cpp`: 2 lines
 - `src/node_stroke_preview.cpp`: 160 lines
 - `src/node_canvas.cpp`: 85 lines
@@ -131,6 +131,16 @@ Latest slice:
   `src/legacy_brush_preset_list_services.*`, and
   `src/legacy_brush_preset_services.*`), leaving
   `src/node_panel_brush.cpp` as a thin translation unit.
+- `Node::load_internal(...)` now routes through
+  `load_legacy_ui_node(...)` in `src/legacy_ui_node_loader.*`, which moves the
+  init/attribute-parse/create/child-load/loaded shell out of `src/node.cpp`.
+- The remaining Win32 shell wrappers for close, async lock/swap, stylus/FPS
+  updates, VR start/stop, window-state save, and the window-handle accessor now
+  live in `src/platform_windows/windows_platform_services.cpp` instead of
+  `src/main.cpp`, leaving `main.cpp` as a thinner entry/runtime dispatcher.
+- The entire `CanvasModeGrid` implementation plus `ActionModeGrid` undo/redo
+  glue now live in `src/legacy_canvas_mode_helpers.cpp` instead of
+  `src/canvas_modes.cpp`, leaving `src/canvas_modes.cpp` as a minimal shell.
 
 Current architecture mismatches that must be treated as real blockers: