Add FileShot.io — zero-knowledge file sharing for CTF teams

Hi! Suggesting FileShot.io for the tools section.

FileShot.io: https://fileshot.io GitHub: https://github.com/FileShot/FileShotZKE License: MIT

For CTF teams: AES-256-GCM encrypted file sharing where the server never sees the plaintext. Good for securely passing challenge files, writeups, or payloads between teammates. No account needed. Free.