feat(expense-snapshot): add ExpenseSnapshot + ExpenseSnapshotLine entities

API/ROLAC.API/Entities/ExpenseSnapshot.cs

@@ -0,0 +1,22 @@
+using ROLAC.API.Entities.Base;
+namespace ROLAC.API.Entities;
+
+/// <summary>
+/// A reusable template of a vendor payment. Lets finance save a recurring fixed expense
+/// (rent, internet, a fixed catered-meal cost) and re-apply it later, pre-filling everything
+/// except the ExpenseDate. Shared church-wide; the creator is the auditable CreatedBy.
+/// Lines are wholly owned by the header (replaced as a set on update, like ExpenseLine).
+/// </summary>
+public class ExpenseSnapshot : SoftDeleteEntity
+{
+    public int      Id          { get; set; }
+    public string   Name        { get; set; } = null!;   // user label, e.g. "Monthly Rent — Landlord X"
+    public int      MinistryId  { get; set; }
+    public string   Description { get; set; } = null!;
+    public string?  VendorName  { get; set; }
+    public string?  CheckNumber { get; set; }
+    public string?  Notes       { get; set; }
+
+    public Ministry?                 Ministry { get; set; }
+    public List<ExpenseSnapshotLine> Lines    { get; set; } = new();
+}

API/ROLAC.API/Entities/ExpenseSnapshotLine.cs

@@ -0,0 +1,18 @@
+using ROLAC.API.Entities.Base;
+namespace ROLAC.API.Entities;
+
+/// <summary>One category line of an <see cref="ExpenseSnapshot"/>, mirroring <see cref="ExpenseLine"/>.</summary>
+public class ExpenseSnapshotLine : AuditableEntity
+{
+    public int      Id              { get; set; }
+    public int      SnapshotId      { get; set; }
+    public int      CategoryGroupId { get; set; }
+    public int      SubCategoryId   { get; set; }
+    public string?  FunctionalClass { get; set; }   // null = inherit Ministry.DefaultFunctionalClass
+    public decimal  Amount          { get; set; }
+    public string?  Description     { get; set; }
+
+    public ExpenseSnapshot?      Snapshot      { get; set; }
+    public ExpenseCategoryGroup? CategoryGroup { get; set; }
+    public ExpenseSubCategory?   SubCategory   { get; set; }
+}