Add per-question LLM/Standard mode toggle for async peer instruction (discussion)

[sethbern]

This PR gives instructors the ability to toggle async peer instruction on and off and choose which PI questions use an LLM. This is what I have so far I would love any feedback, especially with the assignment dashboard since there have been recent changes. @bnmnetp @barbarer

• Instructors can toggle async peer mode on/off from the assignment list

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• Each peer question can be set to LLM or Standard mode individually (defaults to Standard)

  • LLM option only appears when async mode is enabled
  • Edit All lets you bulk switch all questions at once
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• LLM option only shows up if there's a valid API key configured

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• If the API key is broken students get a fallback to standard discussion instead of an error

  • this also works if somebody is in the middle of a conversation with the llm
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• Deleting an API key flips everything back to Standard and re-adding restores previous settings

• Students see a small disclaimer when chatting with the AI peer

[bnmnetp]

I'm torn, I know @barbarer wants this, but very few people use async PI and to add more compexity to this page is worrisome. I understand it is extra clicks to enable, the async, but we cannot have everything on the front page.

I'm thinking about it....

[sethbern]

I think it might make more sense and reduce interface clutter to integrate the async option into the Visibility status dropdown rather than having a separate toggle.

Instead of a standalone async toggle, what if the Visibility dropdown could include an option like "Visible + Async PI (after X time)" that enables async peer instruction when the visibility conditions are met?