Extract app dialog and binding service seams

docs/modernization/roadmap.md

@@ -92,6 +92,13 @@ Current conclusion:
   routes through `src/legacy_app_ui_state_services.*`, so more of the retained
   app shell is down to adapter calls even though runtime draw/event/sidebar
   execution still remains.
+- New-document/save dialog session wiring, app-title rendering, draw-toolbar
+  binding, sidebar stroke-popup binding, and usermanual/changelog/about opener
+  wiring now live in dedicated `legacy_*services.*` seams, so
+  `src/app_dialogs_workflow.cpp`, `src/app_layout.cpp`,
+  `src/app_layout_draw_toolbar.cpp`, `src/app_layout_sidebar.cpp`, and
+  `src/app_dialogs_info_openers.cpp` are thinner adapters even though broader
+  retained dialog/sidebar execution still remains.
 - Platform extraction improved substantially and the root app source group no
   longer compiles Web platform sources directly, but broader CMake and
   entrypoint cleanup are not complete.