feat(1099): add payer EIN to ChurchProfile (entity, DTO, migration)

Add PayerEin (nullable string, max 20) to ChurchProfile entity, AppDbContext
config, ChurchProfileDto response, UpdateChurchProfileRequest, and
ChurchProfileService round-trip — mirroring the Phone/BankRoutingNumber
nullable-string pattern. Migration AddPayerEinToChurchProfile adds only the
one nullable column to ChurchProfiles.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

API/ROLAC.API/Migrations/20260626012205_AddPayerEinToChurchProfile.cs

@@ -0,0 +1,29 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace ROLAC.API.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddPayerEinToChurchProfile : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AddColumn<string>(
+                name: "PayerEin",
+                table: "ChurchProfiles",
+                type: "character varying(20)",
+                maxLength: 20,
+                nullable: true);
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropColumn(
+                name: "PayerEin",
+                table: "ChurchProfiles");
+        }
+    }
+}

API/ROLAC.API/Migrations/AppDbContextModelSnapshot.cs

@@ -506,6 +506,10 @@ namespace ROLAC.API.Migrations
                     b.Property<int>("NextCheckNumber")
                         .HasColumnType("integer");
 
+                    b.Property<string>("PayerEin")
+                        .HasMaxLength(20)
+                        .HasColumnType("character varying(20)");
+
                     b.Property<string>("Phone")
                         .HasMaxLength(50)
                         .HasColumnType("character varying(50)");