chore: rebrand copyright to Firefly Software Foundation

Update copyright notices, NOTICE/LICENSE references, and source
comments to reflect the project's release under the Firefly Software
Foundation per the Apache License 2.0.

Author: Andrés Contreras Guillén

README.md

@@ -339,6 +339,6 @@ Contributions are welcome. Please read the [CONTRIBUTING.md](CONTRIBUTING.md) gu
 
 ## License
 
-Copyright 2024-2026 Firefly Software Solutions Inc.
+Copyright 2024-2026 Firefly Software Foundation.
 
 Licensed under the Apache License, Version 2.0. See [LICENSE](LICENSE) for details.