Overall; fixed design of IState.cs and IReadOnlyState.cs, and fixed namespaces in Beam.Abstractions to remove all references of Beam.Abstract.

Beam.Models/ImmutableState.cs

@@ -1,25 +1,22 @@
 using System.Text.Json.Serialization;
+using Beam.Abstractions;
 
 namespace Beam.Models {
-    public readonly struct ImmutableState {
-        readonly string[] state;
+    public readonly struct ImmutableState : IReadOnlyState {
+        private readonly string[] state;
 
         [JsonConstructor]
-        public ImmutableState(string[] state) {
-            this.state = state ?? [];
+        public ImmutableState(params IEnumerable<string> state) {
+            this.state = state.ToArray();
         }
 
-        public string[] State => state ?? [];
-
-        public readonly Span<string> AsSpan() => state ?? [];
-
+        public ReadOnlySpan<string> GetState() => this.state;
+        
         public readonly State Copy()
             => new((string[])(state ?? []).Clone());
-
-        public readonly string this[Index i] {
-            get => state[i];
-        }
-
+        IState  IReadOnlyState.Copy()
+            => Copy();
+        public readonly string this[Index i] => state[i];
         public static implicit operator State(ImmutableState state)
             => state.Copy();
     }