Add C# bridges and coordinator service

- geviscope-bridge: GeViScope SDK REST wrapper (:7720)
- gcore-bridge: G-Core SDK REST wrapper (:7721)
- geviserver-bridge: GeViServer REST wrapper (:7710)
- copilot-coordinator: WebSocket coordination hub (:8090)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

copilot-coordinator/Models/Messages.cs

@@ -0,0 +1,24 @@
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+namespace CopilotCoordinator.Models;
+
+/// <summary>
+/// WebSocket message envelope for all coordinator events.
+/// </summary>
+public class WsMessage
+{
+    [JsonPropertyName("type")]
+    public string Type { get; set; } = "";
+
+    [JsonPropertyName("data")]
+    public JsonElement? Data { get; set; }
+
+    public static string Serialize(string type, object? data = null)
+    {
+        var msg = new { type, data };
+        return JsonSerializer.Serialize(msg);
+    }
+}
+
+public record KeyboardInfo(string Id, string? Name, DateTime ConnectedAt);