feat: add supplier payment and allocation models, API, and frontend components

- Created `SupplierPayment` and `SupplierPaymentGRN` models for managing supplier payments and their allocations.
- Implemented API endpoints for listing and creating supplier payments.
- Developed frontend components for displaying and recording supplier payments, including a dialog for payment creation.
- Integrated GRN allocations into the payment creation process, ensuring total allocations match the payment amount.
- Added pagination and loading states for the payments list.

Distribution/Models/Payment.cs

@@ -16,5 +16,16 @@ namespace Distribution.Models
         public DateTime CollectedAt { get; set; }
         public Guid CollectedBy { get; set; }
         public Guid? RecordedBy { get; set; }
+
+        // Cash/Bank account that received the funds. Required when Method = Cash;
+        // for Cheque, the FK_ReceivedCheque below carries the deposit account once deposited.
+        public Guid? FK_BankAccountId { get; set; }
+        [ForeignKey("FK_BankAccountId")]
+        public BankAccount? BankAccount { get; set; }
+
+        // Cheque record auto-created when Method = Cheque. Null for Cash/Credit payments.
+        public Guid? FK_ReceivedChequeId { get; set; }
+        [ForeignKey("FK_ReceivedChequeId")]
+        public ReceivedCheque? ReceivedCheque { get; set; }
     }
 }

Distribution/Models/ReceivedCheque.cs

@@ -4,7 +4,7 @@ namespace Distribution.Models
 {
     public class ReceivedCheque : Template
     {
-        public int CompanyId { get; set; }
+        public int? CompanyId { get; set; }
         public int? BranchId { get; set; }
 
         public ReceivedFromType ReceivedFromType { get; set; }

Distribution/Models/SupplierPayment.cs

@@ -0,0 +1,32 @@
+using System.ComponentModel.DataAnnotations.Schema;
+
+namespace Distribution.Models
+{
+    public class SupplierPayment : Template
+    {
+        public Guid FK_SupplierId { get; set; }
+        [ForeignKey("FK_SupplierId")]
+        public Supplier? Supplier { get; set; }
+
+        public decimal Amount { get; set; }
+
+        // Only Cash or Cheque are valid for outgoing payments. Credit is rejected at the service layer.
+        public PaymentMethod Method { get; set; }
+
+        // Cash: required. Null for Cheque.
+        public Guid? FK_BankAccountId { get; set; }
+        [ForeignKey("FK_BankAccountId")]
+        public BankAccount? BankAccount { get; set; }
+
+        // Cheque: required — the ChequePage this payment issued. Null for Cash.
+        public Guid? FK_ChequePageId { get; set; }
+        [ForeignKey("FK_ChequePageId")]
+        public ChequePage? ChequePage { get; set; }
+
+        public DateTime PaidAt { get; set; }
+        public Guid? PaidByUserId { get; set; }
+        public string? Notes { get; set; }
+
+        public ICollection<SupplierPaymentGRN> Allocations { get; set; } = [];
+    }
+}

Distribution/Models/SupplierPaymentGRN.cs

@@ -0,0 +1,19 @@
+using System.ComponentModel.DataAnnotations.Schema;
+using Microsoft.EntityFrameworkCore;
+
+namespace Distribution.Models
+{
+    public class SupplierPaymentGRN : Template
+    {
+        public Guid FK_SupplierPaymentId { get; set; }
+        [ForeignKey("FK_SupplierPaymentId")]
+        public SupplierPayment? SupplierPayment { get; set; }
+
+        public Guid FK_GoodsReceiptId { get; set; }
+        [ForeignKey("FK_GoodsReceiptId")]
+        public GoodsReceipt? GoodsReceipt { get; set; }
+
+        [Precision(18, 2)]
+        public decimal AllocatedAmount { get; set; }
+    }
+}