Own Linux title callback and trim Win32 key state

docs/modernization/tasks.md

@@ -78,6 +78,11 @@ Completed, blocked, and superseded task history moved to
   the queue is now ordered by code movement instead.
 
 Current slice:
+- `linux/src/main.cpp` now owns the Linux FPS-title callback lifecycle
+  directly, and `src/app_events.cpp` no longer installs Linux-specific title
+  behavior from `App::set_platform_services()`.
+- `src/platform_windows/windows_window_shell.*` now stores the Win32 virtual-key
+  map separately from the retained input-state struct.
 - `src/platform_windows/windows_runtime_shell.cpp` no longer stores a second
   retained `App*` alongside `App::I`.
 - `src/platform_windows/windows_window_shell.*` plus