fix: cancel resolved timer timeouts

[DePasqualeOrg]

This PR was developed with Codex using GPT-6 Astra and went through several rounds of automated review. It resolves a real issue that I encountered while using this library.

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Summary

Resolved context timers leave timeout callbacks queued until their deadlines. This PR cancels those callbacks during listener cleanup, releasing resources and preventing callbacks from running after teardown.

How did you test this change?

pnpm test:unit --maxWorkers=2 passes all 471 tests. pnpm build:tsc and pnpm test:lint --threads 2 pass. The new fake-timer regression fails without the fix.

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Latest commit: 513fee3

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