feat(engine,data): add tap-to-select touch input mode (#70)

- Add TouchInputMode enum (OneTap | TapToSelect) to solitaire_data settings
- Create TouchSelectionPlugin with TouchSelectionState resource and highlight
- Branch handle_double_tap: OneTap → existing auto-move, TapToSelect → two-tap flow
- Add Settings UI toggle row (Touch Input Mode) with TouchInputModeText marker
- Register TouchSelectionPlugin in CoreGamePlugin

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

solitaire_engine/src/core_game_plugin.rs

@@ -21,7 +21,8 @@ use crate::{
     RadialMenuPlugin, ReplayOverlayPlugin, ReplayPlaybackPlugin, SafeAreaInsetsPlugin,
     SelectionPlugin, SettingsPlugin, SplashPlugin, StatsPlugin, SyncPlugin, SyncProvider,
     SyncSetupPlugin, TablePlugin, ThemePlugin, ThemeRegistryPlugin, TimeAttackPlugin,
-    UiFocusPlugin, UiModalPlugin, UiTooltipPlugin, WeeklyGoalsPlugin, WinSummaryPlugin,
+    TouchSelectionPlugin, UiFocusPlugin, UiModalPlugin, UiTooltipPlugin, WeeklyGoalsPlugin,
+    WinSummaryPlugin,
 };
 
 /// Groups all Ferrous Solitaire gameplay plugins.
@@ -83,6 +84,7 @@ impl Plugin for CoreGamePlugin {
             .add_plugins(InputPlugin)
             .add_plugins(RadialMenuPlugin)
             .add_plugins(SelectionPlugin)
+            .add_plugins(TouchSelectionPlugin)
             .add_plugins(AnimationPlugin)
             .add_plugins(FeedbackAnimPlugin)
             .add_plugins(CardAnimationPlugin)