Deduplicate in AI integrations

[alexander-alderman-webb]

LangChain is agnostic about input message format:

https://docs.langchain.com/oss/python/langchain/messages#message-content

LiteLLM follows the OpenAI Responses schema for input messages:

https://docs.litellm.ai/docs/completion/input#common-params

Investigate output formats and see if we can deduplicate there as well.

[linear]

PY-2032