normalizeAiAttachmentPayloadFormat

归一化 attachment_payload_format / capabilities.attachmentPayloadFormat （openai | ag_ui | moonshot）。

函数签名

type AiAttachmentPayloadFormat = 'ag_ui' | 'openai' | 'moonshot'

function normalizeAiAttachmentPayloadFormat(v: unknown): AiAttachmentPayloadFormat

工作原理

1. agui / ag_ui → ag_ui
2. moonshot / moonshot_ms / kimi → moonshot（OpenAI 形态 + Files ms://）
3. 未知值默认 openai