docs: refine gRPC guide section numbers and add CloseAndRecv & fileStore explanations

lib/grpc/modular/modular_test.go

@@ -0,0 +1,26 @@
+package modular
+
+import (
+	"net"
+	"testing"
+	"time"
+)
+
+func TestModularServerClient(t *testing.T) {
+	// Find an ephemeral port
+	lis, err := net.Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		t.Fatalf("failed to listen: %v", err)
+	}
+	addr := lis.Addr().String()
+	lis.Close()
+
+	// Start server in background
+	go ServerRun(addr)
+
+	// Wait for server to start
+	time.Sleep(100 * time.Millisecond)
+
+	// Run client against the server
+	ClientRun(addr)
+}