feat(engine): auto-complete badge, confirm dialog, game-over overlay (#56, #57, #58)

Task #56 — HudAutoComplete badge: shows "AUTO" in green when AutoCompleteState.active
is true; announce_auto_complete system fires InfoToastEvent on leading edge.
Task #57 — ConfirmNewGameScreen: intercepts NewGameRequestEvent when move_count > 0 and
is_won=false, shows modal with Y/N keyboard handling.
Task #58 — GameOverScreen: spawns when check_no_moves detects no legal moves; handle_game_over_input
responds to N (new game) and U (undo + despawn). Fix animation system ordering
(chain enqueue_toasts → drive_toast_display) to eliminate flaky test.

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

solitaire_engine/src/animation_plugin.rs

@@ -154,10 +154,9 @@ impl Plugin for AnimationPlugin {
                     handle_settings_toast,
                     handle_auto_complete_toast,
                     handle_new_game_confirm_toast,
-                    enqueue_toasts,
-                    drive_toast_display,
                     handle_xp_awarded_toast,
                     tick_toasts,
+                    (enqueue_toasts, drive_toast_display).chain(),
                 )
                     .after(GameMutation),
             );