Store and Auto-fill OpenRouter API Key for Future Imports

When importing models from OpenRouter, I need to re-enter my OpenRouter API key every time I want to add a new model. However, OpenRouter only shows the API key once when it is generated, and if I haven't saved it somewhere, I can't recover it to use in the future. This makes the process difficult if I forget to store the key, since TypingMind does not remember it.

I would like TypingMind to securely save my OpenRouter API key after I enter it for the first time, and automatically use (or pre-fill) the same key whenever I import more models from OpenRouter. This would prevent me from losing access to my models if I lose the OpenRouter key, and make the import process much smoother.

Thanks for considering this improvement!