Retain Win32 entry state and trim canvas/platform seams

docs/modernization/tasks.md

@@ -143,6 +143,9 @@ 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` heightmap draw callback setup now also routes through
+  `make_legacy_canvas_draw_merge_heightmap_draw(...)`, but the node still owns
+  current-mode traversal and broader post-draw orchestration.
 - `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
@@ -341,6 +344,9 @@ Current slice:
   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
+- `main.cpp` Win32 window handles, GL task/mutex state, splash-dialog state,
+  stylus timers, and VR worker state now sit behind one retained local state
+  object instead of separate file-scope globals
 - retained `App` composition, task call sites, and platform/runtime entrypoint
   coupling are still not fully reduced behind the runtime contract
 
@@ -616,6 +622,9 @@ Current slice:
 - 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`
+- retained GLFW window hooks and the non-Linux fallback storage-path return now
+  also route through retained local state helpers instead of reading `App::I`
+  directly in those method bodies
 - retained Apple callback injection and broader `platform_legacy` singleton
   reach are still open