style(types): add license header to rosocket/index.d.cts

Address Copilot review on #1533: add the standard Apache-2.0 license
header to rosocket/index.d.cts to match the other shipped type
entrypoints (web/index.d.ts, lib/runtime/index.d.ts, rosocket/index.d.ts).

Author: minggangw

rosocket/index.d.cts

@@ -1,3 +1,17 @@
+// Copyright (c) 2026 RobotWebTools Contributors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 // CommonJS type entry for `require('rclnodejs/rosocket')`.
 //
 // Re-exports the ESM declarations so the `require` condition has a CommonJS