Greptile Summary

This PR adds cancellation-aware async selectors across the processor APIs. The main changes are:

• New token-aware SelectAsync and ForEachAsync overloads.
• Linked processor tokens passed to selector callbacks.
• Cleanup waits for in-flight async-enumerable selectors.
• Tests for cancellation through CancelAll, disposal, and external tokens.

Confidence Score: 5/5

This looks safe to merge.

• The updated unbounded processors wait for started selectors during cancellation.
• The result path preserves the exception already leaving enumeration.
• Tests confirm execution stays active until delayed selector cleanup completes.
• No blocking issue remains in the changed code.

Important Files Changed

_{Reviews (2): Last reviewed commit: "fix: await async selector cleanup" | Re-trigger Greptile}