fix: prevent memory leaks from AbortController in async operations

[lkk214]

Description

AbortController instances were not being properly cleaned up after async operations (Promise/AsyncGenerator) completed or failed, leading to potential memory leaks.

Testing

Verified with:

• Run async tasks until completion
• Premature interruption cases
• Memory profiling before/after changes

[netlify]

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🔨 Latest commit	1ffa959

[recurseml]

✨ No issues found! Your code is sparkling clean! ✨

[sestinj]

Thanks for doing this, it's a great fix. I do think it would be good to have a quick test for the runWithAbortController method, since this is going to be on the critical path of every single request. Once there are tests I'm happy to merge!

[lkk214]

Since #5828 still uses the original implementation of addMessageAbortController and abortById, I’ve marked this PR as draft for now. Will update the references here once #5828 is merged.