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/card_animation/mod.rs

@@ -111,10 +111,10 @@ impl Plugin for CardAnimationPlugin {
     fn build(&self, app: &mut App) {
         // Register events and resources that interaction systems depend on,
         // idempotently — double-registration is safe in Bevy.
-        app.add_event::<MoveRequestEvent>()
-            .add_event::<DrawRequestEvent>()
-            .add_event::<UndoRequestEvent>()
-            .add_event::<GameWonEvent>()
+        app.add_message::<MoveRequestEvent>()
+            .add_message::<DrawRequestEvent>()
+            .add_message::<UndoRequestEvent>()
+            .add_message::<GameWonEvent>()
             .init_resource::<DragState>()
             .init_resource::<HoverState>()
             .init_resource::<InputBuffer>()
@@ -163,7 +163,7 @@ impl Plugin for WinCascadePlugin {
 /// Cards scatter to 8 off-screen positions with per-card stagger. The z-lift
 /// creates a "burst" effect as cards fly outward.
 fn trigger_expressive_win_cascade(
-    mut events: EventReader<GameWonEvent>,
+    mut events: MessageReader<GameWonEvent>,
     cards: Query<(Entity, &Transform), With<CardEntity>>,
     layout: Option<Res<LayoutResource>>,
     mut commands: Commands,