CRITICAL - Change license from MIT to AGPL v3

Nobody has claimed this yet.

## What

MinIO uses the AGPL v3 license, this requires any derivative works to also use this license

We are currently using the MIT license, so are not compliant.

## AC

- All source files should start with the AGPL v3 disclaimer

```
FileManager - A simple file management tool.

Copyright (C) 2025 Dan and Luke

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as
published by the Free Software Foundation, either version 3 of the
License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Affero General Public License for more details.

You should have received a copy of the GNU Affero General Public License
along with this program. If not, see .
```

- The full AGPL v3 text must replace the current MIT license

Start by locating the current MIT license and the repository's TypeScript source files. Confirm the AGPL v3 text replaces the MIT license and that every source file begins with the specified AGPL v3 disclaimer; done when both acceptance criteria are satisfied.

Written by the indexing model from the issue text.