🎨 Palette: Polish CLI UX with score formatting and clean UI updates

[aidasofialily-cmd]

This PR introduces several micro-UX enhancements to the Speed Clicker terminal game to improve readability and visual polish.

💡 What: The UX enhancement added

• Score Readability: Added a formatWithCommas helper to provide thousands separators for all score displays (Personal Best, live HUD, and Final Score).
• Clean UI Updates: Replaced manual space padding in the "GO!" prompt and gameplay HUD with the ANSI "Erase in Line" (\033[K) sequence, ensuring a clean terminal state regardless of string length.
• Achievement Context: Modified the post-game screen to display the previous personal best when a new record is set, providing meaningful context for the user's success.
• Macro Consolidation: Removed the redundant RESET macro in favor of the standardized CLR_RESET.

🎯 Why: The user problem it solves

• Large numeric scores were difficult to parse at a glance.
• Manual padding can be brittle and leave trailing characters if strings shorten (though unlikely here, it's a best-practice for CLI tools).
• Setting a new best felt slightly isolated without knowing the previous target that was surpassed.

♿ Accessibility: Any a11y improvements made

• Improved cognitive accessibility by making large numbers easier to read.
• Used standardized ANSI sequences for terminal control, ensuring better compatibility with various terminal emulators.

Verified with make and verify_ux.py.

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PR created automatically by Jules for task 17684848214439175307 started by @aidasofialily-cmd

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