chore: change license to Apache-2.0

[EmanFateen]

Updated description

• Replace the previous license change with Apache License 2.0.
• Update the root LICENSE file to use the Apache License 2.0 text.
• Update package metadata and the lockfile root package entry to use Apache-2.0.
• Update the README license note and PR template license field to reference Apache-2.0.

Previous description

## Summary

- Replace the MIT license text with GNU GPL version 3.
- Update package metadata and the lockfile root package entry to use GPL-3.0-only.
- Update the README license note to say the project is GPLv3 licensed.

## Why GPL-3.0-only instead of GPL-3.0

GPL-3.0-only is the current SPDX identifier for code licensed under exactly GPL version 3. The older GPL-3.0 identifier is deprecated because it does not make the "only this version" intent as explicit. Since this change uses the GPLv3 license text without adding the "or any later version" option to the project metadata, GPL-3.0-only is the precise npm/SPDX value.

If the project should allow GPLv3 or later instead, the correct SPDX identifier would be GPL-3.0-or-later.