Good First Issue: Add --quiet flag to suppress non-error output

[jstreitb]

Problem: Sometimes users want to run baa in the background or in a script and don't want to see the TUI.

Solution: Add a --quiet / -q flag.

• If set, the program should only output essential information or errors.
• Ideally, it should skip the Bubble Tea TUI and just run the updates in the background.

Technical Hint: Check main.go and use the flag package to detect the quiet mode before initializing the Tea program.