Contributor Payment History Query

[Kingsman-99]

Description

There is no way to query all contributions ever made by a specific payer address across all invoices. An indexed payment history keyed by payer should allow wallets and dashboards to retrieve a full contribution history without off-chain indexing.

Technical Context

Store PayerHistory(payer) -> Vec<(invoice_id: u64, amount: i128, ledger: u32)> in storage::persistent in contracts/split/src/lib.rs. Append to this list on every successful contribute. Add get_payer_history(payer: Address, offset: u32, limit: u32) -> Vec<PaymentRecord> with pagination support. Define PaymentRecord in types.rs.

Acceptance Criteria

• Every successful contribute appends a record to PayerHistory(payer)
• get_payer_history returns paginated results using offset and limit
• History includes invoice_id, amount, and ledger for each entry
• History is append-only — withdrawals do not remove entries (only the balance changes)
• List is bounded by a max cap to prevent unbounded storage growth per payer
• All CI checks (cargo build --target wasm32-unknown-unknown, cargo test, cargo clippy) pass and the branch has no merge conflicts

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[neyij]

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

hi, i would like to work on this.

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