feat: add core persistence model

Tiku.Domain/Common/Entity.cs

@@ -0,0 +1,46 @@
+using System.Text.Json;
+
+namespace Tiku.Domain.Common;
+
+public abstract class Entity
+{
+    public Guid Id { get; set; } = Guid.NewGuid();
+}
+
+public interface IHasTimestamps
+{
+    DateTimeOffset CreatedAt { get; set; }
+    DateTimeOffset UpdatedAt { get; set; }
+}
+
+public abstract class AuditableEntity : Entity, IHasTimestamps
+{
+    public DateTimeOffset CreatedAt { get; set; } = DateTimeOffset.UtcNow;
+    public DateTimeOffset UpdatedAt { get; set; } = DateTimeOffset.UtcNow;
+}
+
+public abstract class TenantEntity : Entity
+{
+    public Guid TenantId { get; set; }
+}
+
+public abstract class AuditableTenantEntity : TenantEntity, IHasTimestamps
+{
+    public DateTimeOffset CreatedAt { get; set; } = DateTimeOffset.UtcNow;
+    public DateTimeOffset UpdatedAt { get; set; } = DateTimeOffset.UtcNow;
+}
+
+public static class JsonDefaults
+{
+    public static JsonElement Object()
+    {
+        using var document = JsonDocument.Parse("{}");
+        return document.RootElement.Clone();
+    }
+
+    public static JsonElement Array()
+    {
+        using var document = JsonDocument.Parse("[]");
+        return document.RootElement.Clone();
+    }
+}