🎨 Palette: Improve score readability and UI consistency

[aidasofialily-cmd]

🎨 Palette: Improve score readability and UI consistency

This PR introduces several micro-UX improvements to the SPEED CLICKER terminal game to enhance readability, visual polish, and player feedback.

💡 What: The UX enhancement added

1. Score Formatting: Added a formatWithCommas helper to display large numbers more readably (e.g., 1,250 instead of 1250).
2. Visual Cleanup: Integrated the CLR_EOL (\033[K) ANSI escape sequence to clear the line during \r updates, eliminating "ghost characters" during the countdown and HUD refreshes.
3. HUD Polish: Applied consistent CLR_SCORE (Bold Cyan) styling to both score and high score labels and values for better visual balance.
4. Achievement Context: Updated the Game Over screen to display the previous personal best alongside a new record, providing meaningful context for the achievement.

🎯 Why: The user problem it solves

• Large numbers in the terminal were difficult to parse at a glance.
• Terminal updates occasionally left visual artifacts from previous lines.
• Setting a new personal best felt less rewarding without knowing what the previous record was.

♿ Accessibility

• Improved color contrast and consistency for key game metrics.
• Cleaner terminal output reduces visual noise and potential confusion for users with cognitive or visual impairments.

🛠️ Verification

• Verified with test_format.cpp (standalone logic check).
• Verified with verify_ux.py (terminal standard check).
• Compiled with make (C++11).

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PR created automatically by Jules for task 17024817448185535573 started by @aidasofialily-cmd

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