Harden runtime flags and thin Apple/canvas seams

docs/modernization/tasks.md

@@ -143,6 +143,10 @@ Current slice:
   draw, heightmap draw, and current-mode draw now also route through
   `execute_legacy_canvas_draw_merge_post_draw(...)`, but broader canvas draw
   orchestration is still inline.
+- `NodeCanvas` smoothing-mask face shader setup plus per-face draw execution
+  now also route through
+  `execute_legacy_canvas_draw_merge_smask_faces(...)`, but the node still owns
+  the broader canvas draw flow and renderer-state sequencing around that seam.
 - `NodeCanvas` non-`draw_merged` per-layer/per-plane retained draw execution
   now also routes through `execute_legacy_canvas_draw_merge_layer_plane(...)`,
   but the node still owns substantial live layer traversal and renderer state
@@ -335,6 +339,8 @@ Current slice:
   live in `AppRuntime`
 - `AppRuntime` render/UI worker ownership now also uses `std::jthread` plus
   explicit stop requests instead of raw `std::thread`
+- Windows main-loop run-state and VR worker coordination flags in `main.cpp`
+  now use `std::atomic` ownership instead of unsynchronized globals
 - retained `App` composition, task call sites, and platform/runtime entrypoint
   coupling are still not fully reduced behind the runtime contract
 
@@ -604,6 +610,9 @@ Current slice:
 - Apple crash-test, app-close, and iOS SonarPen hooks now also route through
   explicit Apple bridge callbacks instead of direct `App::I` calls in
   `LegacyPlatformServices`
+- retained Apple ObjC handles plus storage paths now live in one local
+  `platform_legacy` helper, and the iOS SonarPen bridge now starts through
+  that retained Apple state instead of reading `App::I` inside the bridge body
 - Linux/Web GLFW render-context acquire/present hooks and Linux app-close now
   also route through retained local GLFW callback hooks instead of direct
   method-body `App::I` access in `LegacyPlatformServices`