Feature/send headers when using node event source transport

__tests__/client.comprehensive.test.ts

@@ -59,7 +59,15 @@ describe("MultiServerMCPClient", () => {
 
       // Initialize connections and verify
       await client.initializeConnections();
-      expect(SSEClientTransport).toHaveBeenCalled();
+      expect(SSEClientTransport).toHaveBeenCalledWith(
+        new URL(config["test-server"].url),
+        {
+          eventSourceInit: {},
+          requestInit: {
+            headers: config["test-server"].headers,
+          },
+        }
+      );
       expect(Client).toHaveBeenCalled();
     });
 

src/client.ts

@@ -613,9 +613,8 @@ export class MultiServerMCPClient {
 
       // For Extended EventSource, create the SSE transport
       return new SSEClientTransport(new URL(url), {
-        // Pass empty options for test compatibility
         eventSourceInit: {},
-        requestInit: {},
+        requestInit: { headers },
       });
     } catch (extendedError) {
       // Fall back to standard eventsource if extended-eventsource is not available