Phase E: Add Bank Reconciliation

- IsCleared + ClearedDate added to Payment, BillPayment, Expense entities
- BankReconciliation entity (account, statement date, beginning/ending balance, status)
- BankReconciliationStatus enum (InProgress, Completed)
- Migration AddBankReconciliation: new BankReconciliations table + IsCleared/ClearedDate columns
- IUnitOfWork/UnitOfWork wired with BankReconciliations repo
- BankReconciliationsController: Index, Create, Reconcile, ToggleCleared (AJAX), Complete, Report
- Reconcile view: deposit/payment checkboxes with live running balance and difference via JS
- Complete is gated: only enabled when difference == $0.00
- Nav: Bank Reconciliation added to Finance section in _Layout

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

src/PowderCoating.Web/Views/Shared/_Layout.cshtml

@@ -1138,6 +1138,10 @@
                             <i class="bi bi-arrow-return-left"></i>
                             <span>Vendor Credits</span>
                         </a>
+                        <a asp-controller="BankReconciliations" asp-action="Index" class="nav-link">
+                            <i class="bi bi-bank2"></i>
+                            <span>Bank Reconciliation</span>
+                        </a>
                         if (hasReports)
                         {
                             <a asp-controller="AccountingExport" asp-action="Index" class="nav-link">