feat(data,engine): implement NativeStorage and WasmStorage backends (closes #48)

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

solitaire_engine/src/core_game_plugin.rs

@@ -8,6 +8,7 @@ use std::sync::Mutex;
 
 use bevy::prelude::*;
 
+use crate::platform::{StorageBackendResource, default_storage_backend};
 use crate::{
     AchievementPlugin, AnalyticsPlugin, AnimationPlugin, AssetSourcesPlugin, AudioPlugin,
     AutoCompletePlugin, AvatarPlugin, CardAnimationPlugin, CardPlugin, ChallengePlugin,
@@ -44,6 +45,15 @@ impl Plugin for CoreGamePlugin {
             .take()
             .expect("CoreGamePlugin::build called twice");
 
+        match default_storage_backend() {
+            Ok(storage) => {
+                app.insert_resource(StorageBackendResource(storage));
+            }
+            Err(err) => {
+                warn!("storage: failed to initialize platform backend: {err}");
+            }
+        }
+
         app.add_plugins(AssetSourcesPlugin)
             .add_plugins(ThemePlugin)
             .add_plugins(ThemeRegistryPlugin)