Add WebSockets (#1423)

* Add WebSockets

* Add tests

* fix

* more tests

* Add tests

* ...

* remove IOwin

* -

* tests

* fluent

* ok

* match

* .

* byte[]

* x

* func

* func

* byte

* trans

* ...

* frameworks.........

* jmes

* xxx

* sc

src/WireMock.Net.Minimal/WebSockets/WebSocketConnectionRegistry.cs

@@ -0,0 +1,60 @@
+// Copyright © WireMock.Net
+
+using System.Collections.Concurrent;
+using System.Diagnostics.CodeAnalysis;
+using System.Linq;
+using System.Net.WebSockets;
+
+namespace WireMock.WebSockets;
+
+/// <summary>
+/// Registry for managing WebSocket connections per mapping
+/// </summary>
+internal class WebSocketConnectionRegistry
+{
+    private readonly ConcurrentDictionary<Guid, WireMockWebSocketContext> _connections = new();
+
+    /// <summary>
+    /// Add a connection to the registry
+    /// </summary>
+    public void AddConnection(WireMockWebSocketContext context)
+    {
+        _connections.TryAdd(context.ConnectionId, context);
+    }
+
+    /// <summary>
+    /// Remove a connection from the registry
+    /// </summary>
+    public void RemoveConnection(Guid connectionId)
+    {
+        _connections.TryRemove(connectionId, out _);
+    }
+
+    /// <summary>
+    /// Get all connections
+    /// </summary>
+    public IReadOnlyCollection<WireMockWebSocketContext> GetConnections()
+    {
+        return _connections.Values.ToList();
+    }
+
+    /// <summary>
+    /// Try to get a specific connection
+    /// </summary>
+    public bool TryGetConnection(Guid connectionId, [NotNullWhen(true)] out WireMockWebSocketContext? connection)
+    {
+        return _connections.TryGetValue(connectionId, out connection);
+    }
+
+    /// <summary>
+    /// Broadcast text to all connections
+    /// </summary>
+    public async Task BroadcastTextAsync(string text, CancellationToken cancellationToken = default)
+    {
+        var tasks = _connections.Values
+            .Where(c => c.WebSocket.State == WebSocketState.Open)
+            .Select(c => c.SendAsync(text, cancellationToken));
+
+        await Task.WhenAll(tasks);
+    }
+}