Thin canvas modes, node execution, and canvas draw shell

docs/modernization/roadmap.md

@@ -81,12 +81,12 @@ Current hotspot files:
 
 - `src/canvas.cpp`: 2728 lines
 - `src/app_layout.cpp`: 125 lines
-- `src/canvas_modes.cpp`: 1798 lines
-- `src/node.cpp`: 1465 lines
+- `src/canvas_modes.cpp`: 1710 lines
+- `src/node.cpp`: 1368 lines
 - `src/main.cpp`: 271 lines
 - `src/node_panel_brush.cpp`: 1207 lines
 - `src/node_stroke_preview.cpp`: 910 lines
-- `src/node_canvas.cpp`: 852 lines
+- `src/node_canvas.cpp`: 864 lines
 - `src/app.cpp`: 575 lines
 - `src/app_dialogs.cpp`: 168 lines
 
@@ -240,13 +240,24 @@ Current architecture mismatches that must be treated as real blockers:
   `src/node_stroke_preview.cpp`, while the immediate preview pass-sequencing
   family inside `draw_stroke_immediate()` now also routes through
   `NodeStrokePreview::execute_stroke_draw_immediate_pass_sequence(...)`, while
+  `NodeCanvas::draw()` unmerged-pass blend-gate, layer-orientation, and
+  callback-assembly setup now also route through
+  `execute_node_canvas_draw_unmerged_pass(...)`, which trims another coherent
+  unmerged draw shell from the live node even though the file itself remains
+  large, 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
   preview stroke preparation, dual-brush setup, and live pass-orchestration
   request assembly now also route through retained preview execution helpers,
   while `Node` child attach/detach/reorder operations now route through named
   local helpers in `src/node.cpp`, and `Node::load_internal(...)` child XML
   loading now also routes through `src/legacy_ui_node_loader.*`, which makes
   the scene-graph mutation and child-instantiation paths easier to reason
-  about without yet reducing the file or moving ownership into `pp_ui_core`,
+  about without yet moving ownership into `pp_ui_core`, while the generic
+  per-frame node execution/traversal family for `restore_context`,
+  `clear_context`, `update`, `update_internal`, and `tick` now also lives in
+  `src/legacy_ui_node_execution.cpp`,
   while `Canvas` point-trace/unproject/project/camera push-pop-get-set and
   face-to-shape helpers now also route through
   `src/legacy_canvas_projection_services.*` instead of staying inline in

docs/modernization/tasks.md

@@ -108,6 +108,11 @@ Current slice:
   `src/legacy_canvas_projection_services.*` instead of staying inline in
   `src/canvas.cpp`, which trims another coherent non-UI state/query pocket
   from the live canvas shell.
+- Shared canvas-mode GL wrappers plus the `CanvasModeBasicCamera` and
+  `CanvasModeCamera` input handlers now also live in
+  `src/legacy_canvas_mode_helpers.*` instead of staying inline in
+  `src/canvas_modes.cpp`, which trims another coherent retained canvas-view
+  interaction pocket from the broader canvas/render hotspot family.
 
 Write scope:
 - `src/canvas.cpp`
@@ -252,6 +257,12 @@ Current slice:
   `execute_legacy_canvas_draw_node_canvas_unmerged_pass(...)`, which
   materially shortens the live `NodeCanvas::draw()` body even though the file
   itself is still large.
+- `NodeCanvas::draw()` unmerged-pass blend-gate query, layer-orientation
+  assembly, and callback wiring into
+  `execute_legacy_canvas_draw_node_canvas_unmerged_pass(...)` now also route
+  through `execute_node_canvas_draw_unmerged_pass(...)`, which trims another
+  coherent unmerged draw-orchestration block from the live node even though
+  the file size remains roughly flat.
 
 Write scope:
 - `src/node_stroke_preview.cpp`
@@ -673,6 +684,11 @@ Current slice:
   That trims another coherent generic node-instantiation pocket and makes the
   remaining scene-graph load path easier to isolate, even though ownership has
   not yet moved into `pp_ui_core`.
+- The generic per-frame node execution/traversal family for
+  `restore_context`, `clear_context`, `update`, `update_internal`, and `tick`
+  now also lives in `src/legacy_ui_node_execution.cpp` instead of staying
+  inline in `src/node.cpp`, which materially thins the base scene-graph file
+  without changing its public surface.
 
 Write scope:
 - `src/node.cpp`