Window comes back at its last size, position and maximized state

Saved on resize, move, maximize and close; on start (and hot restart)
the normal size and maximized state come back everywhere, the position
on Windows and X11 when it still lands on a display (Wayland places
windows itself).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

apps/desktop/pubspec.yaml

@@ -23,6 +23,7 @@ dependencies:
   hive_ce_flutter: ^2.3.4
   image: ^4.9.2
   window_manager: ^0.5.2
+  screen_retriever: ^0.2.2
   crypto: ^3.0.6
   ffi: ^2.1.0
   # Drag & drop and clipboard files/images (vendored desktop_drop + pasteboard).