feat(transport): add a headless boot path for the HTTP plugin hub

MCPForUnity/Editor/McpHttpCiBoot.cs

@@ -0,0 +1,57 @@
+using System;
+using MCPForUnity.Editor.Constants;
+using MCPForUnity.Editor.Helpers;
+using MCPForUnity.Editor.Services;
+using MCPForUnity.Editor.Services.Transport;
+using UnityEditor;
+
+namespace MCPForUnity.Editor
+{
+    // HTTP is a plugin-hub pull model: the bridge waits at ws://127.0.0.1:<port>/hub/plugin
+    // and the editor must dial in. StartStdioForCi forces stdio and only listens, so an
+    // editor booted that way never registers and every call returns no_unity_session.
+    //
+    // The port comes from UNITY_MCP_HTTP_PORT rather than a pref because sibling checkouts
+    // of one project share an EditorPrefs file, so a persisted HttpUrl is clobbered by
+    // whichever editor wrote last.
+    public static class McpHttpCiBoot
+    {
+        private const string PortEnv = "UNITY_MCP_HTTP_PORT";
+
+        // Re-asserted on every domain load so a reload cannot resume a sibling's port
+        [InitializeOnLoadMethod]
+        private static void ReassertEndpointFromEnv()
+        {
+            ApplyEndpointFromEnv();
+        }
+
+        public static void StartHttpForCi()
+        {
+            if (!ApplyEndpointFromEnv())
+            {
+                McpLog.Error($"[MCPForUnity] StartHttpForCi: {PortEnv} not set or invalid; cannot start HTTP transport");
+                return;
+            }
+
+            // Defer the connect so MCPServiceLocator and friends are initialized.
+            EditorApplication.delayCall += () =>
+            {
+                _ = MCPServiceLocator.TransportManager.StartAsync(TransportMode.Http);
+            };
+        }
+
+        private static bool ApplyEndpointFromEnv()
+        {
+            string portStr = Environment.GetEnvironmentVariable(PortEnv);
+            if (string.IsNullOrWhiteSpace(portStr) || !int.TryParse(portStr, out int port) || port <= 0)
+            {
+                return false;
+            }
+
+            EditorPrefs.SetBool(EditorPrefKeys.UseHttpTransport, true);
+            EditorPrefs.SetString(EditorPrefKeys.HttpTransportScope, "local");
+            EditorPrefs.SetString(EditorPrefKeys.HttpBaseUrl, $"http://127.0.0.1:{port}");
+            return true;
+        }
+    }
+}