🎨 Palette: Add explicit empty state for highscore

[EiJackGH]

💡 What: Added an explicit empty state ("None yet! Set one!") for the highscore.
🎯 Why: To clarify system state and improve user onboarding by explicitly acknowledging the lack of a highscore, rather than just hiding the text.
📸 Before/After: Visual change in terminal output on first run.
♿ Accessibility: Improves clarity and understanding of the game's state.

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PR created automatically by Jules for task 10868652746282208282 started by @EiJackGH

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