Reusable UniColl MD5 collisions on Pickle files

[kryjak]

Hello, I adapted your methodology to create reusable MD5 collisions between Pickle files, based on UniColl. Please see here for details. I also tried doing the same for Safetensors, but failed - I don't think it's possible because it's a much more rigid file structure. I would appreciate:

• having my PR reviewed
• letting me know if you think there are other AI-relevant file formats that can be exploited similarly
• letting me know if you have in mind some realistic attack scenarios specific to Pickle files, or any improvements over this work