feat: add runtime i18n API with manifest translations

lib/runtime/game/flame_lua_game.dart

@@ -181,6 +181,25 @@ class FlameLuaGame extends FlameGame with PanDetector, ScrollDetector {
       _resources = activation.resources;
       _audio = activation.audio ?? _createAudioManager();
       _scriptEngine = activation.scriptEngine;
+
+      // 合并所有包的翻译字典，框架包先、游戏包后，后加载的覆盖先加载的。
+      final mergedTranslations = <String, Map<String, String>>{};
+      for (final package in activation.packages) {
+        for (final entry in package.manifest.translations.entries) {
+          mergedTranslations.putIfAbsent(entry.key, () => {})
+              .addAll(entry.value);
+        }
+      }
+      final resolvedLocale = RuntimeLocaleResolver.resolve(
+        requested: _localeOverride ?? PlatformDispatcher.instance.locale,
+        defaultLocale: activation.package.manifest.defaultLocale,
+        supportedLocales: activation.package.manifest.supportedLocales,
+      );
+      _scriptEngine.setTranslations(
+        locale: resolvedLocale.resolved,
+        translations: mergedTranslations,
+      );
+
       _viewportConfig = activation.package.manifest.display.toViewportConfig();
       _viewportRoot = PositionComponent();
       add(_viewportRoot);