Add EF Core-backed subscription storage for ServiceControl

src/ServiceControl.Persistence.EFCore.PostgreSql/Migrations/20260729053645_AddSubscriptions.cs

@@ -0,0 +1,34 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace ServiceControl.Persistence.EFCore.PostgreSql.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddSubscriptions : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.CreateTable(
+                name: "subscriptions",
+                columns: table => new
+                {
+                    message_type = table.Column<string>(type: "character varying(200)", maxLength: 200, nullable: false),
+                    transport_address = table.Column<string>(type: "character varying(200)", maxLength: 200, nullable: false),
+                    endpoint = table.Column<string>(type: "character varying(450)", maxLength: 450, nullable: false)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("pk_subscriptions", x => new { x.message_type, x.transport_address });
+                });
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropTable(
+                name: "subscriptions");
+        }
+    }
+}

src/ServiceControl.Persistence.EFCore.PostgreSql/Migrations/PostgreSqlServiceControlDbContextModelSnapshot.cs

@@ -316,6 +316,30 @@ protected override void BuildModel(ModelBuilder modelBuilder)
                     b.ToTable("known_endpoints", (string)null);
                 });
 
+            modelBuilder.Entity("ServiceControl.Persistence.EFCore.Entities.SubscriptionEntity", b =>
+                {
+                    b.Property<string>("MessageType")
+                        .HasMaxLength(200)
+                        .HasColumnType("character varying(200)")
+                        .HasColumnName("message_type");
+
+                    b.Property<string>("TransportAddress")
+                        .HasMaxLength(200)
+                        .HasColumnType("character varying(200)")
+                        .HasColumnName("transport_address");
+
+                    b.Property<string>("Endpoint")
+                        .IsRequired()
+                        .HasMaxLength(450)
+                        .HasColumnType("character varying(450)")
+                        .HasColumnName("endpoint");
+
+                    b.HasKey("MessageType", "TransportAddress")
+                        .HasName("pk_subscriptions");
+
+                    b.ToTable("subscriptions", (string)null);
+                });
+
             modelBuilder.Entity("ServiceControl.Persistence.EFCore.Entities.TrialMetadataEntity", b =>
                 {
                     b.Property<int>("Id")