Improve tap command response handling with error reporting

[pkkid]

This solves issue #17.

Before:

• Simply printed the debug output of the result: println!("{result:?}")

After:

• Properly handles success and error cases separately
• For successful responses:
  • Displays "(empty response)" when the response is empty
  • Displays the actual response string cleanly (without debug formatting)
• For errors: displays them with debug formatting prefixed by "Error:"

This makes the interactive TAP command interface more user-friendly by showing clean output instead of Rust's debug representation for successful responses.

[tchebb]

Hi Michael! Thanks for all your contributions over the past few days. I know I've been neglecting this project, and I want to get back to it. Unfortunately, I'm currently in the middle of an international move and don't have time to review anything in the immediate future. I should have time in mid-February, though.

[pkkid]

No worries. It's speaker software, we shouldn't need to feel rushed. :D
I hope your move goes well!