DeepSeek-V3.2-Exp released, both API model entries upgraded

DeepSeek-V3.2-Exp

Both deepseek-chat and deepseek-reasoner have been upgraded to DeepSeek-V3.2-Exp. deepseek-chat maps to non-thinking mode and deepseek-reasoner to thinking mode; details are in the docs.

Why it matters: DeepSeek upgraded both API entries to DeepSeek-V3.2-Exp, with the two call names mapping to non-thinking and thinking mode.