🎨 Palette: Micro-UX improvements for game start and high-score celebrations

[aidasofialily-cmd]

This PR implements several micro-UX improvements in src/main.cpp to make the game more engaging and rewarding.

Key changes include:

• Visual Guidance: Interaction keywords ("any key") and countdown digits are now highlighted in Bold Yellow, drawing the user's focus to the current state and required actions.
• Clear Transitions: The "GO!" message now uses Bold Green, providing a strong visual cue that the game has started.
• Inclusive Achievements: Previously, a "NEW BEST!" message would only appear if the user already had a high score. I've updated the logic so that a user's very first game (where score > 0) is celebrated as a personal best, providing immediate positive reinforcement.
• Terminal Hygiene: Added a reset code to the score update line to ensure formatting doesn't bleed into the terminal after the game ends.

These small touches align with the goal of making the interface more pleasant and intuitive.

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PR created automatically by Jules for task 12086782055441712083 started by @aidasofialily-cmd

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