Extract canvas layer flows, pen modes, and node attributes

docs/modernization/roadmap.md

@@ -79,10 +79,10 @@ What is still carrying too much live ownership:
 
 Current hotspot files:
 
-- `src/canvas.cpp`: 1490 lines
+- `src/canvas.cpp`: 1271 lines
 - `src/app_layout.cpp`: 125 lines
-- `src/canvas_modes.cpp`: 1014 lines
-- `src/node.cpp`: 995 lines
+- `src/canvas_modes.cpp`: 720 lines
+- `src/node.cpp`: 803 lines
 - `src/main.cpp`: 271 lines
 - `src/node_panel_brush.cpp`: 435 lines
 - `src/node_stroke_preview.cpp`: 751 lines
@@ -264,11 +264,18 @@ Current architecture mismatches that must be treated as real blockers:
   `Canvas::stroke_draw()` orchestration now also routes through
   `src/legacy_canvas_stroke_live_services.cpp` instead of staying inline in
   `src/canvas.cpp`, which materially thins another large retained live
-  stroke-render pocket, while the
+  stroke-render pocket, while `Canvas::layer_merge(...)`,
+  `Canvas::flood_fill(...)`, and `Canvas::FloodData::apply()` now also route
+  through `src/legacy_canvas_layer_services.cpp` instead of staying inline in
+  `src/canvas.cpp`, which trims another coherent retained layer/fill workflow
+  pocket, while the
   `CanvasModeTransform` interaction family now also routes through
   `src/legacy_canvas_mode_transform.cpp` instead of staying inline in
   `src/canvas_modes.cpp`, which materially thins another retained canvas-view
-  and transform-mode execution pocket,
+  and transform-mode execution pocket, while the `CanvasModePen` and
+  `CanvasModeLine` interaction families now also route through
+  `src/legacy_canvas_mode_pen_line.cpp` instead of staying inline in
+  `src/canvas_modes.cpp`,
   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
@@ -306,7 +313,9 @@ Current architecture mismatches that must be treated as real blockers:
   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`,
+  `src/legacy_ui_node_execution.cpp`, while `Node::parse_attributes(...)` now
+  also routes through `src/legacy_ui_node_attributes.*` instead of staying
+  inline in `src/node.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

@@ -91,7 +91,7 @@ Status: In Progress
 
 Why now:
 `src/canvas.cpp` is still the biggest single architectural blocker at about
-1490 lines, with `src/canvas_modes.cpp` still large at about 1014 lines.
+1271 lines, with `src/canvas_modes.cpp` still large at about 720 lines.
 
 Current slice:
 - Canvas state-management helpers for picking, clear/clear-all, layer
@@ -130,6 +130,15 @@ Current slice:
   `src/legacy_canvas_stroke_live_services.cpp` instead of staying inline in
   `src/canvas.cpp`, which materially thins another large retained live
   stroke-render pocket from the canvas shell.
+- `Canvas::layer_merge(...)`, `Canvas::flood_fill(...)`, and
+  `Canvas::FloodData::apply()` now also live in
+  `src/legacy_canvas_layer_services.cpp` instead of staying inline in
+  `src/canvas.cpp`, which trims another coherent retained layer/fill workflow
+  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
+  interaction pocket from the broader canvas/render hotspot family.
 
 Write scope:
 - `src/canvas.cpp`
@@ -728,6 +737,10 @@ Current slice:
   `src/legacy_ui_node_event.*` instead of staying inline in `src/node.cpp`,
   which materially thins the base scene-graph event shell without changing its
   public surface.
+- `Node::parse_attributes(...)` now also routes through
+  `src/legacy_ui_node_attributes.*` instead of staying inline in `src/node.cpp`,
+  which trims another coherent XML/Yoga attribute decoding pocket from the base
+  scene-graph shell without changing its public surface.
 
 Write scope:
 - `src/node.cpp`