feat(i18n): Implement server-side internationalization support

- Added ServerI18nManager to handle translations and locale settings on the server.
- Integrated server-side translations into templates, reducing language flashing on initial load.
- Created API endpoints for setting and getting user language preferences.
- Enhanced client-side i18n handling to work seamlessly with server-rendered content.
- Updated various templates to utilize the new translation system.
- Added mixed i18n handler to coordinate server and client translations, improving user experience.
- Expanded translation files to include initialization messages for various components.

py/routes/recipe_routes.py

@@ -17,6 +17,7 @@ from ..recipes import RecipeParserFactory
 from ..utils.constants import CARD_PREVIEW_WIDTH
 
 from ..services.settings_manager import settings
+from ..services.server_i18n import server_i18n
 from ..config import config
 
 # Check if running in standalone mode
@@ -127,6 +128,17 @@ class RecipeRoutes:
             # Ensure services are initialized
             await self.init_services()
             
+            # 获取用户语言设置
+            user_language = settings.get('language', 'en')
+            
+            # 设置服务端i18n语言
+            server_i18n.set_locale(user_language)
+            
+            # 为模板环境添加i18n过滤器
+            if not hasattr(self.template_env, '_i18n_filter_added'):
+                self.template_env.filters['t'] = server_i18n.create_template_filter()
+                self.template_env._i18n_filter_added = True
+            
             # Skip initialization check and directly try to get cached data
             try:
                 # Recipe scanner will initialize cache if needed
@@ -136,7 +148,18 @@ class RecipeRoutes:
                     recipes=[],  # Frontend will load recipes via API
                     is_initializing=False,
                     settings=settings,
-                    request=request
+                    request=request,
+                    user_language=user_language,
+                    # 添加服务端翻译函数
+                    t=server_i18n.get_translation,
+                    server_i18n=server_i18n,
+                    # 添加一些常用的翻译到上下文
+                    common_translations={
+                        'loading': server_i18n.get_translation('common.status.loading'),
+                        'error': server_i18n.get_translation('common.status.error'),
+                        'refresh': server_i18n.get_translation('common.actions.refresh'),
+                        'search': server_i18n.get_translation('common.actions.search'),
+                    }
                 )
             except Exception as cache_error:
                 logger.error(f"Error loading recipe cache data: {cache_error}")
@@ -145,7 +168,16 @@ class RecipeRoutes:
                 rendered = template.render(
                     is_initializing=True,
                     settings=settings,
-                    request=request
+                    request=request,
+                    user_language=user_language,
+                    # 添加服务端翻译函数
+                    t=server_i18n.get_translation,
+                    server_i18n=server_i18n,
+                    # 添加一些常用的翻译到上下文
+                    common_translations={
+                        'loading': server_i18n.get_translation('common.status.loading'),
+                        'error': server_i18n.get_translation('common.status.error'),
+                    }
                 )
                 logger.info("Recipe cache error, returning initialization page")