35c6b880f7
* Fix Mistral cached token usage Map prompt cache hits from Mistral chat usage into the standard usage details. Add regression coverage for regular and streaming responses. * Validate Mistral cached token usage * fix(mistral): satisfy strict cached token typing Narrow prompt token details before reading cached_tokens so the Mistral package passes strict Pyright without changing runtime validation.\n\nAddresses https://github.com/microsoft/agent-framework/pull/7597#discussion_r3750712320