Add support for using ConversationID for AzureOpenAI and OpenAI

[ViveliDuCh]

Fixes #6313

Implement support for stateful conversations, enabling the use of conversationId in the Microsoft.Extensions.AI chat web template. Add backend logic to the template for dynamically selecting stateful or stateless chat clients at runtime, enabling use of experimental stateful APIs like GetOpenAIResponseClient for supporting providers (AzureOpenAI, OpenAI), and laying the groundwork for future provider support.
Providers like Ollama and GitHubModels currently use the legacy, stateless GetChatClient due to lack of stateful API support.

Note: Use GetOpenAIResponseClient only with providers that support it—namely AzureOpenAI and OpenAI. Avoid using it with Ollama and GitHubModels, which throw runtime errors due to lack of support for the ResponseStreamingChatClient interface.

Microsoft Reviewers: Open in CodeFlow

[Copilot]

Pull Request Overview

This PR adds support for stateful conversations by implementing conversationID functionality in Microsoft.Extensions.AI.WebChatTemplate. The changes enable conversation state management by switching from GetChatClient to GetOpenAIResponseClient for OpenAI and AzureOpenAI providers while maintaining compatibility with providers that don't support the Responses interface.

• Switch from GetChatClient to GetOpenAIResponseClient for OpenAI/AzureOpenAI providers to enable conversationID support
• Implement conversation state management by tracking conversationID in chat options and updating it from streaming responses

Reviewed Changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
Chat.razor	Updates streaming response handling to pass only user message when the conversation is stateful (conversationId not null), skipping the rest of the message history based on the conversationID.
Program.cs	Replaces GetChatClient with GetOpenAIResponseClient/AddResponsesChatClient calls for the providers that support it.

Note: Adds inline NoWarn directive to suppress OPENAI001 warnings.

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[ViveliDuCh]

@dotnet-policy-service agree company="Microsoft"

[jozkee]

Otherwise, LGTM!

[MackinnonBuck]

This is looking great! Just a few suggestions.

[jeffhandley]

Talking with @stephentoub about this, we should consider another approach to these changes. The template should produce a project that handles both stateful and stateless conversations.

@ViveliDuCh / @jozkee - We can chat more about the implications of this different approach.

[MackinnonBuck]

The template should produce a project that handles both stateful and stateless conversations.

I believe something like what I suggested here should handle both cases. We only submit the a subset of the converstaion history if the latest response update specified a ConversationId. Otherwise, the full conversation is sent every time.