Extract app dialog and binding service seams

docs/modernization/tasks.md

@@ -101,6 +101,29 @@ Key facts:
   `App&`, popup-root, trigger-button, and panel dependencies, so
   `src/app_layout_sidebar.cpp` is thinner while the retained stroke/grid/layer
   popup families still remain inline.
+- `App::dialog_usermanual()`, `App::dialog_changelog()`, and
+  `App::dialog_about()` now delegate the retained info-dialog construction and
+  overlay close wiring through `src/legacy_info_dialog_services.*` with
+  explicit `App&` plus overlay-anchor dependencies, so
+  `src/app_dialogs_info_openers.cpp` is thinner while `open_whatsnew_dialog()`
+  still owns the retained whats-new flow inline.
+- `App::dialog_newdoc()` and `App::dialog_save()` now delegate retained dialog
+  construction and button wiring through `src/legacy_document_session_services.*`,
+  so `src/app_dialogs_workflow.cpp` is thinner at the document-session seam
+  while browse, open, and resize retained workflows still remain there.
+- `App::title_update()` now delegates retained document-title and DPI-label
+  rendering through `src/legacy_app_status_services.*`, so
+  `src/app_layout.cpp` no longer owns that app-status family inline.
+- `App::init_toolbar_draw()` now delegates retained draw-toolbar button lookup,
+  click wiring, and default-tool application through
+  `src/legacy_draw_toolbar_binding_services.*`, so
+  `src/app_layout_draw_toolbar.cpp` is down to a thin adapter while retained
+  tool execution still flows through `src/legacy_canvas_tool_services.*`.
+- `App::init_sidebar()` now delegates the retained stroke-popup open/anchor/tick
+  wiring through `src/legacy_sidebar_stroke_popup_services.*` with explicit
+  `App&`, popup-root, trigger-button, and panel dependencies, so
+  `src/app_layout_sidebar.cpp` is thinner while the retained grid and layer
+  popup families still remain inline.
 
 ## Parallel Assignment Rules