Extract canvas plane data, brush preset list, and WinMain bridge

docs/modernization/tasks.md

@@ -148,6 +148,10 @@ Current slice:
   `src/legacy_canvas_render_shell_services.*` instead of staying inline in
   `src/canvas.cpp`, which trims another large retained render/context shell
   from the live canvas owner.
+- The static canvas plane geometry/orientation data now also lives in
+  `src/legacy_canvas_plane_data.cpp` instead of staying inline in
+  `src/canvas.cpp`, which trims another retained data-ownership pocket from
+  the live canvas shell.
 - The `CanvasModePen` and `CanvasModeLine` interaction families now also live
   in `src/legacy_canvas_mode_pen_line.cpp` instead of staying inline in
   `src/canvas_modes.cpp`, which materially thins another retained pen/line
@@ -651,6 +655,9 @@ Current slice:
   in `src/platform_windows/windows_window_shell.*` instead of `src/main.cpp`,
   which materially thins the entry file even though broader runtime/entrypoint
   composition is still open
+- the `WinMain` argv conversion bridge now also lives in
+  `src/platform_windows/windows_bootstrap_helpers.*` instead of staying inline
+  in `src/main.cpp`, which trims another Windows-specific entrypoint pocket
 - retained input-state zeroing and reverse key-map initialization now also live
   in `src/platform_windows/windows_window_shell.*` instead of `src/main.cpp`,
   which trims another small but real retained-state pocket from the entry TU
@@ -1115,6 +1122,10 @@ Current slice:
   `src/node_panel_brush.cpp`, which materially thins another retained preset
   panel UI pocket even though cloud/package worker ownership remains the
   follow-up.
+- The retained `LegacyBrushPresetListServices` block now also lives in
+  `src/legacy_brush_preset_list_services.*` instead of staying inline in
+  `src/node_panel_brush.cpp`, which trims another retained preset workflow
+  pocket while preserving the live list-plan dispatch path.
 - `NodePanelBrush` brush texture panel init, selection dispatch,
   popup-close event handling, restore-failure prompt flow, and added-state
   reset now also live in `src/legacy_brush_panel_ui.*` instead of staying