Audit finding 9a: a cash refund posted DR AR (control up) while the customer
subledger went down — opposite directions, guaranteeing AR drift. Per the chosen
model, a cash refund now *reverses the sale*: DR Sales Returns (revenue portion)
+ DR Sales Tax Payable (tax portion) / CR Bank, with the customer AR balance left
untouched (the invoice stays paid; the sale is contra'd).
- New 4960 "Sales Returns & Allowances" contra-revenue account (seed + self-heal).
- Tax/revenue split centralized in Core RefundAllocation.Split so the posting and
both reporting recomputes compute it identically (a mismatch would unbalance the
trial balance).
- InvoicesController IssueRefund/CancelRefund: new posting + reversal; no AR/
customer-balance change.
- LedgerService (per-account + prior balance): refunds debit Sales Returns + Sales
Tax, no longer debit AR; bank credit unchanged.
- FinancialReportService: trial balance, balance sheet (retained earnings + tax
liability), and P&L (contra-revenue line) all updated to match. Store-credit
refunds are excluded everywhere (they post via CreditMemo, not the GL — 9b).
Verified: $108 refund (incl. $8 tax) -> bank -100... checks: assets -108 =
liabilities -8 + equity -100. New tests cover the split invariant and the ledger
postings. Build clean; 283 unit tests pass.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
spouliot