🎨 Palette: Add encouraging empty state for initial high score

[EiJackGH]

What: Added an encouraging empty state ("None yet! Start clicking!") for the "Personal Best" section when the high score is zero.
Why: To improve onboarding and clarify to the user that the system tracks high scores, rather than just hiding the section.
Before/After: The "Personal Best" section is now visible even on the first run.
Accessibility: Improves clarity of system state for all users.

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PR created automatically by Jules for task 14713006375281338759 started by @EiJackGH

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