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

lib/grpc/http3/http3_test.go

@@ -0,0 +1,26 @@
+package http3
+
+import (
+	"testing"
+	"time"
+)
+
+func TestHttp3ServerClient(t *testing.T) {
+	// Start server on ephemeral port
+	lis, cleanup, err := ServerRun("127.0.0.1:0")
+	if err != nil {
+		t.Fatalf("failed to start server: %v", err)
+	}
+	defer cleanup()
+
+	addr := lis.Addr().String()
+
+	// Wait for server to be fully ready
+	time.Sleep(100 * time.Millisecond)
+
+	// Run client against the server
+	err = ClientRun(addr)
+	if err != nil {
+		t.Fatalf("client run failed: %v", err)
+	}
+}