* Added a dedicated effect to merge origin and selected models, ensuring selected items always remain in the dropdown list.
* Enhanced “Copy all models” button:
* Shows info message when list is empty.
* Displays success / error notification based on copy result.
* Unified UI look-and-feel by applying `!rounded-lg` class to inputs, selects, banners and buttons.
* i18n: added English translations for new prompts
- "No models to copy"
- "Model list copied to clipboard"
- "Copy failed"
