Cannot tap defenseunicorns/tap: invalid syntax in tap!

### Environment

Device and OS: Debian 13 (trixie)
App version: latest on brew tap
Kubernetes distro being used: N/A
Other:

### Steps to reproduce

1. on a fresh (in my case debian) box, run the brew trust/tap/install commands from the readme
2. you will see an error in the terminal

### Expected result
The CLI should be installed with no errors

### Actual Result
See the attachment

[tap-failure.md](https://github.com/user-attachments/files/32171651/tap-failure.md)

### Visual Proof (screenshots, videos, text, etc)

### Severity/Priority
High

### Additional Context
I'm on a brand new debian vm that I just installed brew on.

$ brew --version
Homebrew 7.0.1

Reproduce the README's brew trust, tap, and install commands on Debian 13 with Homebrew 7.0.1, then review the attached tap-failure.md and terminal output to identify where the tap syntax fails. Done means the CLI installs from a fresh Debian environment without errors.

Written by the indexing model from the issue text.