Extract canvas stroke commit and brush preset services

docs/modernization/roadmap.md

@@ -79,14 +79,14 @@ What is still carrying too much live ownership:
 
 Current hotspot files:
 
-- `src/canvas.cpp`: 2592 lines
+- `src/canvas.cpp`: 2122 lines
 - `src/app_layout.cpp`: 125 lines
 - `src/canvas_modes.cpp`: 1626 lines
 - `src/node.cpp`: 1368 lines
 - `src/main.cpp`: 271 lines
-- `src/node_panel_brush.cpp`: 1094 lines
+- `src/node_panel_brush.cpp`: 652 lines
 - `src/node_stroke_preview.cpp`: 910 lines
-- `src/node_canvas.cpp`: 872 lines
+- `src/node_canvas.cpp`: 877 lines
 - `src/app.cpp`: 575 lines
 - `src/app_dialogs.cpp`: 168 lines
 
@@ -251,12 +251,24 @@ Current architecture mismatches that must be treated as real blockers:
   while `Canvas::draw_objects_direct(...)` and `Canvas::draw_objects(...)` now
   route through `src/legacy_canvas_object_draw_services.*` instead of staying
   inline in `src/canvas.cpp`, which trims another coherent object-draw and
+  viewport-state execution family from the live canvas shell, while
+  `Canvas::stroke_draw_samples(...)`, `Canvas::stroke_commit()`, and the
+  larger stroke commit/sample execution family now also route through
+  `src/legacy_canvas_stroke_commit_services.*` instead of staying inline in
+  `src/canvas.cpp`, which trims another large retained stroke-render and
   viewport-state execution family from the live canvas shell,
   while `NodePanelBrush` save/restore/scan/reload/find/get-path ownership now
   routes through `src/legacy_brush_panel_services.*` instead of staying inline
   in `src/node_panel_brush.cpp`, which trims another retained brush-workflow
   pocket from the live UI node even though the broader panel still remains
-  large, while shared canvas-mode GL wrappers plus the
+  large, while `NodePanelBrushPreset` save/restore and package
+  import/export/import-ABR routing now also lives in
+  `src/legacy_brush_preset_services.*` instead of staying inline in
+  `src/node_panel_brush.cpp`, which trims another large preset-workflow pocket
+  from the live UI node, while `NodeCanvas::handle_event()` now also routes
+  through `execute_node_canvas_handle_event(...)`, which trims another coherent
+  input-routing block from `src/node_canvas.cpp` even though the file is still
+  a live canvas/controller shell, while shared canvas-mode GL wrappers plus the
   `CanvasModeBasicCamera` and `CanvasModeCamera` input handlers now also route
   through `src/legacy_canvas_mode_helpers.*` instead of staying inline in
   `src/canvas_modes.cpp`, while