Invoice Payment Progress Tracker

[Kingsman-99]

Description

Long-running invoice payments with multiple tranches or async recipient claims have no unified progress representation in the SDK. Callers poll individual operations independently, producing inconsistent UX. A progress tracker should aggregate all per-recipient payment states into a single InvoicePaymentProgress object that can be subscribed to and rendered progressively.

Technical Context

Add src/paymentProgressTracker.ts. Aggregates RecipientPaymentState[] from src/types.ts. Uses src/poller.ts per recipient to fetch operation status. Emits invoiceProgressUpdated events via src/events.ts with { invoiceId, percentComplete, recipientStates } payloads. Integrates with src/trancheProgress.ts for tranche-based invoices. Exposes a subscribe(invoiceId, callback) API.

Acceptance Criteria

• PaymentProgressTracker.subscribe(invoiceId, onProgress) starts polling all recipient payment legs and calls onProgress on each status change
• InvoicePaymentProgress.percentComplete is computed as the number of settled legs divided by total legs × 100
• Each RecipientPaymentState includes accountId, status, settledAmount, and lastUpdatedAt
• unsubscribe(invoiceId) cancels all underlying pollers for that invoice
• Unit tests mock per-recipient Horizon responses and assert percentComplete increments correctly as legs settle
• All CI checks (npm test, npm run build, ESLint/TypeScript) pass and the branch has no merge conflicts

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[CELIAu1]

@CELIAu1 has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

Hi maintainer, I'd like to take on this issue.

I specialize in Backend and frontend development with Golang, Next.js and TypeScript. My experience allows me to bridge functionality with intuitive user experiences, ensuring both technical correctness and usability.

I'll follow the existing codebase conventions, communicate progress clearly, and deliver a high-quality solution within the expected timeline.

Thank you for your consideration.

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[D-Ochuko]

@D-Ochuko has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

I would like to work on this.
Please assign

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