Add client-side Notes page with API integration and shared contracts

Freman.Sample.Web.Contracts/CreateNoteRequest.cs

@@ -0,0 +1,10 @@
+using System.ComponentModel.DataAnnotations;
+
+namespace Freman.Sample.Web.Contracts;
+
+public sealed class CreateNoteRequest
+{
+    [Required]
+    [StringLength(500)]
+    public string Text { get; set; } = "";
+}