Add project files.

Management/Security/ClientContext.cs

@@ -0,0 +1,20 @@
+namespace Management.Security;
+
+/// <summary>
+/// Request-scoped authentication context.
+/// Populated by ClientAuthMiddleware.
+/// </summary>
+public sealed class ClientContext
+{
+    public string? SessionId { get; set; }
+    public string? ClientId { get; set; }
+    public string? PlatformClientId { get; set; }
+    public string? ClientName { get; set; }
+    public string? UserId { get; set; }
+    public string? Email { get; set; }
+    public string? Role { get; set; }
+    public bool IsDevBypass { get; set; }
+
+    public bool IsAuthenticated => !string.IsNullOrWhiteSpace(ClientId);
+    public bool IsAdmin => string.Equals(Role, "Admin", StringComparison.OrdinalIgnoreCase);
+}