Thin Windows runtime globals and legacy GLFW hooks

docs/modernization/tasks.md

@@ -78,6 +78,9 @@ Completed, blocked, and superseded task history moved to
   the queue is now ordered by code movement instead.
 
 Current slice:
+- `src/platform_windows/windows_runtime_shell.cpp` no longer keeps a separate
+  retained `AppRuntime*`; the touched Windows lifecycle and main-thread task
+  dispatch paths now derive runtime ownership directly from the owned app.
 - `src/platform_windows/windows_runtime_shell.cpp` now owns the Windows `App`
   through a retained `std::unique_ptr<App>`, so startup/early-return/convert
   paths no longer manage raw `new`/`delete` app lifetime manually.
@@ -87,6 +90,9 @@ Current slice:
 - `src/platform_windows/windows_window_shell.cpp` now routes the touched
   key-map synchronization and VR close state through narrow helpers instead of
   carrying the broader retained window bundle live across the window-proc path.
+- `src/platform_legacy/legacy_platform_state.*` no longer exports the mutable
+  retained GLFW hook bundle; Linux/Web fallback render-context, present, and
+  app-close paths now route through narrow GLFW helper functions instead.
 - `scripts/automation/quiet-validate.ps1` now owns the recommended quiet
   checkpoint path and can bundle Windows build/test, Android/platform sweeps,
   and Apple remote compile gates into one compact JSON summary with