Add `invoice_id` to `late_payment_penalty_charged` event data payload

[Kingsman-99]

Description

late_payment_penalty_charged in contracts/split/src/events.rs publishes with topics ("late_pen", invoice_id) — the invoice_id is already the second topic, so indexers can filter by it. However the event does not include invoice_id in the data payload, making data-only decoders unable to identify which invoice was affected.

Acceptance Criteria

• Update late_payment_penalty_charged to include invoice_id in the event data: (invoice_id, payer, penalty_amount)
• Update any existing tests for this event
• cargo test passes

Context

• Target file: contracts/split/src/events.rs

[Silver36-ship-it]

@Silver36-ship-it has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

I would love to work on this professionally, please assign it to me

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[Rejoice2374]

@Rejoice2374 has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Hi, I’d like to work on issue #611.

The current late_payment_penalty_charged event already includes invoice_id as a topic, but adding it to the data payload would make the event self-contained for data-only consumers and indexers.

I’ll update the event in contracts/split/src/events.rs so its data payload becomes:

(invoice_id, payer, penalty_amount)

I’ll also review and update the existing tests to assert the new payload structure and ensure there are no other affected event consumers or expectations.

Finally, I’ll run cargo test to verify the change passes the full test suite without introducing regressions.

I’ll keep the implementation focused on the event and its associated tests while maintaining the existing event naming and topic conventions.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Rejoice2374 to this issue.

[Chronos-III]

@Chronos-III has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

hi team kindly assign me i can work on this issue am a software developer

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Congratulations, @Chronos-III! 🎉 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!

@Chronos-III's PR #659 was approved and merged by @Kingsman-99.

🏆 @Chronos-III: You earned 35 FoxPoints for this contribution! Your current tier: Explorer (48 total points). Track your full progress on GrantFox.

👏 Great work, @Chronos-III! Keep contributing to Stellar-split.

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

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