Extract node events, transform mode, and preview pass shells

docs/modernization/roadmap.md

@@ -81,11 +81,11 @@ Current hotspot files:
 
 - `src/canvas.cpp`: 2122 lines
 - `src/app_layout.cpp`: 125 lines
-- `src/canvas_modes.cpp`: 1626 lines
-- `src/node.cpp`: 1368 lines
+- `src/canvas_modes.cpp`: 1014 lines
+- `src/node.cpp`: 995 lines
 - `src/main.cpp`: 271 lines
 - `src/node_panel_brush.cpp`: 652 lines
-- `src/node_stroke_preview.cpp`: 910 lines
+- `src/node_stroke_preview.cpp`: 751 lines
 - `src/node_canvas.cpp`: 877 lines
 - `src/app.cpp`: 575 lines
 - `src/app_dialogs.cpp`: 168 lines
@@ -240,6 +240,10 @@ 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
+  the remaining immediate preview pass shell now also routes through
+  `execute_legacy_node_stroke_preview_draw_immediate_shell(...)`, which
+  materially reduces the live preview-pass body even though broader
+  worker/readback flow still remains inline, 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
@@ -256,7 +260,11 @@ Current architecture mismatches that must be treated as real blockers:
   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,
+  viewport-state execution family from the live canvas shell, 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,
   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
@@ -274,7 +282,11 @@ Current architecture mismatches that must be treated as real blockers:
   `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
+  while `Node::on_event(...)` plus mouse/key capture and release ownership now
+  also route through `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, 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

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
-2122 lines.
+2122 lines, with `src/canvas_modes.cpp` still large at about 1014 lines.
 
 Current slice:
 - Canvas state-management helpers for picking, clear/clear-all, layer
@@ -122,6 +122,10 @@ Current slice:
   `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.
+- The `CanvasModeTransform` interaction family now also lives in
+  `src/legacy_canvas_mode_transform.cpp` instead of staying inline in
+  `src/canvas_modes.cpp`, which materially thins another retained
+  transform-mode pocket from the broader canvas/render hotspot family.
 
 Write scope:
 - `src/canvas.cpp`
@@ -182,6 +186,11 @@ Current slice:
   which trims another coherent setup pocket from
   `src/node_stroke_preview.cpp` even though worker/readback ownership and
   broader preview flow still remain inline.
+- The remaining immediate preview pass shell in
+  `NodeStrokePreview::draw_stroke_immediate()` now also routes through
+  `execute_legacy_node_stroke_preview_draw_immediate_shell(...)`, which
+  materially reduces the live preview-pass body even though worker/readback
+  ownership still remains inline.
 - `NodeCanvas` merged-path per-plane merged-texture draw execution now also
   routes through `execute_legacy_canvas_draw_merge_layer_texture(...)`.
 - `NodeCanvas` merged-path and non-blend checkerboard background setup now also
@@ -706,6 +715,10 @@ Current slice:
   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.
+- `Node::on_event(...)` plus mouse/key capture and release now also live in
+  `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.
 
 Write scope:
 - `src/node.cpp`