Credit AR for gift-certificate redemptions in balance recompute (audit O7)

ApplyGiftCertificate posts DR 2500 Gift Certificate Liability / CR AR, but the AR
recompute only subtracted payments and credit-memo applications — so the redemption's
2500 debit was recomputed while its AR credit was not, leaving the Trial Balance out
of balance by the total gift-certificate amount redeemed and overstating AR on the
Balance Sheet.

Subtract GC redemptions from AR in both recompute engines:
  - FinancialReportService: Balance Sheet (gcRedeemedBs) and Trial Balance (gcRedeemedTb)
  - LedgerService: AR section (dated rows) and ComputePriorBalanceAsync (prior balance)

AR Aging was already correct (uses BalanceDue, which includes GiftCertificateRedeemed).
Adds a LedgerService regression test. Build clean; 292 unit tests pass.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/PowderCoating.Infrastructure/Services/FinancialReportService.cs

@@ -365,6 +365,13 @@ public class FinancialReportService : IFinancialReportService
             .Where(a => a.CompanyId == companyId && a.AppliedDate <= asOfEnd && a.Invoice.Status != InvoiceStatus.Voided)
             .SumAsync(a => (decimal?)a.AmountApplied) ?? 0;
         arCredits += cmAppliedBs;
+        // Gift-certificate redemptions also credit AR (ApplyGiftCertificate posts DR 2500 / CR AR).
+        // Mirror the posting here so AR is not overstated and the entry's two sides stay balanced.
+        var gcRedeemedBs = await _context.GiftCertificateRedemptions
+            .Where(r => r.CompanyId == companyId && !r.IsDeleted && r.RedeemedDate <= asOfEnd
+                     && r.Invoice.Status != InvoiceStatus.Voided)
+            .SumAsync(r => (decimal?)r.AmountRedeemed) ?? 0;
+        arCredits += gcRedeemedBs;
 
         // Customer Credits (2350): a credit memo books DR Sales Discounts / CR Customer Credits on issue,
         // then DR Customer Credits / CR AR on apply. Contra-revenue (retained earnings) = issued amount
@@ -1132,6 +1139,13 @@ public class FinancialReportService : IFinancialReportService
                      && p.Invoice.Status != InvoiceStatus.WrittenOff)
             .SumAsync(p => (decimal?)p.Amount) ?? 0m;
         arTotalCredits += cmApplied; // credit memo applications reduce AR balance
+        // Gift-certificate redemptions credit AR too (DR 2500 / CR AR). Without this the redemption's
+        // 2500 debit is recomputed but its AR credit is not, leaving the trial balance out of balance.
+        var gcRedeemedTb = await _context.GiftCertificateRedemptions
+            .Where(r => r.CompanyId == companyId && !r.IsDeleted && r.RedeemedDate <= asOfEnd
+                     && r.Invoice.Status != InvoiceStatus.Voided)
+            .SumAsync(r => (decimal?)r.AmountRedeemed) ?? 0m;
+        arTotalCredits += gcRedeemedTb;
 
         // Cash refunds reverse the sale: revenue portion → DR Sales Returns (4960), tax portion →
         // DR Sales Tax Payable (relieves the liability), cash → CR bank (refundsByAcct below). They no

src/PowderCoating.Infrastructure/Services/LedgerService.cs

@@ -350,6 +350,27 @@ public class LedgerService : ILedgerService
                     LinkId = cm.InvoiceId
                 });
 
+            // Gift-certificate redemptions reduce open AR (CREDIT) — ApplyGiftCertificate posts DR 2500 / CR AR.
+            var arGcRedemptions = await _context.GiftCertificateRedemptions
+                .Include(r => r.Invoice)
+                .Include(r => r.GiftCertificate)
+                .Where(r => !r.IsDeleted && r.RedeemedDate >= fromDate && r.RedeemedDate <= toDate
+                         && r.Invoice.Status != InvoiceStatus.Voided)
+                .ToListAsync();
+
+            foreach (var r in arGcRedemptions)
+                entries.Add(new LedgerEntryDto
+                {
+                    Date = r.RedeemedDate,
+                    Reference = r.GiftCertificate?.CertificateCode ?? $"GC-{r.GiftCertificateId}",
+                    Source = "Gift Certificate",
+                    Description = $"GC redeemed on {r.Invoice?.InvoiceNumber}",
+                    Debit = 0,
+                    Credit = r.AmountRedeemed,
+                    LinkController = "Invoices",
+                    LinkId = r.InvoiceId
+                });
+
             // NOTE: cash refunds no longer touch AR. Under the "reverse the sale" model they debit
             // Sales Returns + Sales Tax Payable and credit the bank (see section 5b above).
         }
@@ -751,6 +772,11 @@ public class LedgerService : ILedgerService
                 .Where(a => a.AppliedDate < beforeDate && a.Invoice.Status != InvoiceStatus.Voided)
                 .SumAsync(a => (decimal?)a.AmountApplied) ?? 0;
 
+            // Gift-certificate redemptions credit AR (DR 2500 / CR AR), same as in GetAccountLedgerAsync.
+            credits += await _context.GiftCertificateRedemptions
+                .Where(r => !r.IsDeleted && r.RedeemedDate < beforeDate && r.Invoice.Status != InvoiceStatus.Voided)
+                .SumAsync(r => (decimal?)r.AmountRedeemed) ?? 0;
+
             // NOTE: cash refunds no longer debit AR — they reverse the sale (Sales Returns + Sales Tax),
             // handled in section 5b above.
         }