Enhance copyright notice for clarity and compliance

[jserv]

Each source file in this repository currently starts with the following notice:

// This file is part of the TEN Framework project.
// See https://github.com/TEN-framework/ten_framework/LICENSE for license
// information.

While this provides basic information, it deviates from common open-source practices by omitting the copyright owner's name and the year. To improve clarity and align with standard conventions, I suggest updating the notice to:

// Copyright (c) 2024 Agora
// This is free software; you can redistribute it and/or modify it under the
// terms of the Apache license, Version 2.0. A copy of the license can be found in the file
// "LICENSE" at the root of this distribution.

This enhancement will make the copyright notice more verbose and relevant, ensuring it meets typical open-source licensing standards.

Example projects:

• mimalloc
• airflow

[halajohn]

Hi, I have modified the file header to include the description of the copyright owner and added some license information. If there are any issues with the content of the license, I can address them here or create a dedicated discussion to document it.

[jserv]

Close via #21