Close all GL entry gaps across the accounting surface

- Stripe payments/refunds/chargebacks now post DR/CR entries (PaymentController)
- Vendor credit void now reverses the posted GL lines (VendorCreditsController)
- Gift certificate issue/redeem/void post GL to account 2500 GC Liability;
  FinancialReportService Trial Balance + Balance Sheet include GC liability and
  breakage income; P&L shows deferred revenue deduction and breakage income line
- Customer deposits now post DR Checking / CR 2300 on record, reverse on delete;
  invoice auto-apply uses DR 2300 / CR AR (not a second bank debit); draft
  invoice delete reverses deposit-apply GL before the AR reversal
- Deposit.DepositAccountId column added; account 2300 seeded via migration
- InvoicesController.ApplyCredit now posts DR Sales Discounts / CR AR,
  consistent with CreditMemosController.Apply
- IssueRefund (cash/card) posts DR AR / CR Bank and sets Refund.DepositAccountId;
  refund modal gains a bank account selector hidden for store-credit path
- CancelRefund (cash/card) reverses the IssueRefund GL entries
- LedgerService GetAccountLedgerAsync + ComputePriorBalanceAsync now include
  Refunds, CreditMemoApplications, VendorCreditApplications, GC Liability (2500),
  and Customer Deposits (2300) so account ledger view and RecalculateAllAsync
  produce correct balances
- Three EF migrations applied: SeedSalesDiscountsAccount, AccountingGapsPhase2,
  AccountingDepositsGL
- Unit tests updated for new IAccountBalanceService constructor params (200/200)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/PowderCoating.Web/Views/Invoices/Details.cshtml

@@ -1145,6 +1145,20 @@
                             <option value="5">Store Credit</option>
                         </select>
                     </div>
+                    <div class="mb-3" id="refundDepositAccountRow">
+                        <label class="form-label fw-semibold">Refund From Account</label>
+                        <select name="DepositAccountId" class="form-select">
+                            <option value="">(Not tracked)</option>
+                            @if (ViewBag.BankAccounts != null)
+                            {
+                                @foreach (var acct in (IEnumerable<SelectListItem>)ViewBag.BankAccounts)
+                                {
+                                    <option value="@acct.Value">@acct.Text</option>
+                                }
+                            }
+                        </select>
+                        <div class="form-text">Bank or cash account the refund is paid from.</div>
+                    </div>
                     <div class="mb-3">
                         <label class="form-label fw-semibold">Reason <span class="text-danger">*</span></label>
                         <input type="text" name="Reason" class="form-control" placeholder="e.g. Warranty claim, duplicate charge..." required />
@@ -1171,6 +1185,7 @@
                     document.getElementById('refundAlertCash').classList.toggle('d-none', isCredit);
                     document.getElementById('refundAlertCredit').classList.toggle('d-none', !isCredit);
                     document.getElementById('refundReferenceRow').classList.toggle('d-none', isCredit);
+                    document.getElementById('refundDepositAccountRow').classList.toggle('d-none', isCredit);
                 });
             </script>
         </div>