feat: Add new model management features

- Implement `/api/channel/models_enabled` endpoint to retrieve enabled models
- Add `EnabledListModels` handler in controller
- Create new `ModelRatioNotSetEditor` component for managing unset model ratios
- Update router to include new models_enabled route
- Add internationalization support for new model management UI
- Include GPT-4.5 preview model in OpenAI model list

relay/channel/openai/constant.go

@@ -11,6 +11,7 @@ var ModelList = []string{
 	"chatgpt-4o-latest",
 	"gpt-4o", "gpt-4o-2024-05-13", "gpt-4o-2024-08-06", "gpt-4o-2024-11-20",
 	"gpt-4o-mini", "gpt-4o-mini-2024-07-18",
+	"gpt-4.5-preview", "gpt-4.5-preview-2025-02-27",
 	"o1-preview", "o1-preview-2024-09-12",
 	"o1-mini", "o1-mini-2024-09-12",
 	"o3-mini", "o3-mini-2025-01-31",