Own log worker and trim Apple platform hooks

docs/modernization/roadmap.md

@@ -100,7 +100,7 @@ Current architecture mismatches that must be treated as real blockers:
   remain, even though iOS keyboard visibility and prepared-file save handoff
   now also route through explicit Apple bridge callbacks and Apple render-
   context hooks plus iOS main-render-target binding now route through the same
-  bridge style.
+  bridge style, as do Apple crash-test, app-close, and iOS SonarPen hooks.
 - `src/platform_legacy/legacy_platform_services.*` is still part of the live
   app shell.
 - `pp_panopainter_ui` still depends on `pp_legacy_app`.
@@ -108,7 +108,8 @@ Current architecture mismatches that must be treated as real blockers:
   OpenGL execution around the renderer boundary, even though `NodeCanvas`
   display resolve, cache-to-screen composite, post-draw mask/grid/current-mode
   sequencing, per-layer/per-plane retained draw execution, and shared
-  checkerboard background setup now route through retained draw-merge helpers.
+  checkerboard background setup now route through retained draw-merge helpers,
+  with the cache-to-screen checkerboard-plane callback setup also reduced.
 - `app_layout.cpp` and `app_dialogs.cpp` are still mixed shell/controller files
   rather than thin composition/binding surfaces.
 - `App`, `Canvas`, `Node`, retained workers, and platform entrypoints still use
@@ -118,7 +119,8 @@ Current architecture mismatches that must be treated as real blockers:
   launches now use owned `std::jthread` or service-owned worker queues and
   `AppRuntime` now owns render/UI workers with explicit `std::jthread`
   shutdown semantics while the Windows splash-dialog and HMD renderer workers
-  also use owned `std::jthread` lifecycle.
+  also use owned `std::jthread` lifecycle and `LogRemote` now uses the same
+  ownership model.
 - Modern C++23 usage exists in extracted components, especially `std::span`,
   explicit result/status objects, and a few concepts, but the live app still
   does not consistently express ownership, thread affinity, or renderer