Chore: Add an official LICENSE file

[fred-maina]

Description

The project is currently "all rights reserved" by default because it lacks a LICENSE file. This creates legal ambiguity for potential contributors. To be a proper open-source project, it needs an explicit license.

The pom.xml has a <licenses> tag, but it's empty.

Acceptance Criteria

1. Choose an appropriate open-source license (e.g., MIT, Apache 2.0).
2. Create a LICENSE file at the root of the repository.
3. Copy the full text of the chosen license into this file.
4. Update the <licenses> section in pom.xml to reflect the chosen license (e.g., name and URL).