make account service with grn

Backend/ERPCore/Domain/Entities/Grn.cs

@@ -30,8 +30,18 @@ public class Grn
     public DateTime CreatedAt { get; set; }
     public DateTime? PostedAt { get; set; }
 
+    /// <summary>Journal number of the real GL journal entry posted for this GRN's receipt (set on confirm).</summary>
+    public string? GlJournalNo { get; set; }
+    public DateTime? GlPostedAt { get; set; }
+
+    /// <summary>Sum of vendor payments made against this GRN's total payable (<see cref="GrnLine.LineTotal"/>).</summary>
+    public decimal PaidAmount { get; set; }
+    /// <summary>Total payable minus <see cref="PaidAmount"/>; installments accrue against this until it reaches zero.</summary>
+    public decimal BalanceAmount { get; set; }
+
     /// <summary>PostgreSQL xmin-backed optimistic concurrency token.</summary>
     public uint RowVersion { get; set; }
 
     public ICollection<GrnLine> Lines { get; set; } = new List<GrnLine>();
+    public ICollection<GrnPayment> Payments { get; set; } = new List<GrnPayment>();
 }

Backend/ERPCore/Domain/Entities/GrnPayment.cs

@@ -0,0 +1,31 @@
+namespace ERPCore.Domain.Entities;
+
+/// <summary>
+/// A vendor payment made against a confirmed GRN's balance (installments allowed —
+/// see GrnPaymentService.PayAsync). Posts its own real GL journal entry (Debit GRN
+/// Clearing / Credit the selected bank-or-cash account) before being recorded here.
+/// </summary>
+public class GrnPayment
+{
+    public int GrnPaymentId { get; set; }
+
+    public int GrnId { get; set; }
+    public Grn? Grn { get; set; }
+
+    public decimal Amount { get; set; }
+    public DateTime PaymentDate { get; set; }
+
+    /// <summary>GL's numeric id for the bank/cash account the payment was made from.</summary>
+    public long GlBankAccountId { get; set; }
+    /// <summary>Snapshot of the account's display name at payment time (GL account lists have no local FK).</summary>
+    public string BankAccountName { get; set; } = string.Empty;
+
+    public string? Reference { get; set; }
+
+    /// <summary>Journal number of the real GL journal entry this payment posted.</summary>
+    public string? GlJournalNo { get; set; }
+
+    public int CreatedBy { get; set; }
+    public User? Creator { get; set; }
+    public DateTime CreatedAt { get; set; }
+}