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/hud_plugin.rs

@@ -475,7 +475,7 @@ fn update_selection_hud(
 /// to debounce so the toast only appears on the leading edge.
 fn announce_auto_complete(
     auto_complete: Option<Res<AutoCompleteState>>,
-    mut toast: EventWriter<InfoToastEvent>,
+    mut toast: MessageWriter<InfoToastEvent>,
     mut was_active: Local<bool>,
 ) {
     let now_active = auto_complete.as_ref().is_some_and(|ac| ac.active);