chore(deps): migrate to Bevy 0.17

- Event/EventReader/EventWriter renamed to Message/MessageReader/MessageWriter
- add_event → add_message for all 67 call sites
- ScrollPosition changed to tuple struct ScrollPosition(Vec2)
- CursorIcon import moved from bevy::winit::cursor to bevy::window
- WindowResolution::from((f32,f32)) removed — use (u32,u32) tuple
- World::send_event → World::write_message in test code

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

solitaire_engine/src/selection_plugin.rs

@@ -162,8 +162,8 @@ fn handle_selection_keys(
     paused: Option<Res<PausedResource>>,
     game: Res<GameStateResource>,
     mut selection: ResMut<SelectionState>,
-    mut moves: EventWriter<MoveRequestEvent>,
-    mut info_toast: EventWriter<InfoToastEvent>,
+    mut moves: MessageWriter<MoveRequestEvent>,
+    mut info_toast: MessageWriter<InfoToastEvent>,
 ) {
     if paused.is_some_and(|p| p.0) {
         return;