InvoiceListSentinel does not disconnect IntersectionObserver on unmount

[Kingsman-99]

Description

InvoiceListSentinel creates an IntersectionObserver to trigger infinite-scroll loading but does not call observer.disconnect() when the component unmounts. This causes stale callbacks to fire after navigation, which can trigger redundant API calls.

Acceptance Criteria

• The IntersectionObserver is disconnected inside a useEffect cleanup function
• No stale callbacks fire after the component unmounts
• Infinite scroll continues to work correctly during normal use
• Existing tests continue to pass

Context

• Target file: src/components/InvoiceListSentinel.tsx

[AvatarMiiDe]

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[lolandriley-wq]

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I will like to work on this issue please

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Congratulations, @lolandriley-wq! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on August 31, 2026.

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[grantfox-oss]

🎉 This issue has been marked as completed on GrantFox as part of the Third Campaign campaign!

@lolandriley-wq's PR #645 was approved and merged by @Kingsman-99.

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This issue has been completed by @lolandriley-wq as part of the Stellar Wave Program's 8th Wave 🥳

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