DeepSeek V4.1 Flash in the agent picker

Agent chats that pick DeepSeek Flash now use the V4.1 generation.

DeepSeek V4.1 Flash now powers the DeepSeek Flash entry in the agent picker.

If you already selected DeepSeek Flash, new chats use the V4.1 generation when OpenRouter can serve it. Auto also uses DeepSeek V4.1 Flash first. DeepSeek V4 Pro is unchanged.