🎨 Palette: Improve Mario game UX with instructions and ARIA roles

[EiJackGH]

💡 What:

• Added a visual instruction text element ("Press Space or Up Arrow to jump") below the score.
• Added aria-live="polite" and aria-atomic="true" to the score counter.

🎯 Why:

• Users relying on keyboard controls didn't have explicit, intuitive indications of what keys mapped to the jump action.
• Dynamic score updates were not being correctly announced by screen readers.

📸 Before/After:
(See visual changes in commit history/screenshots: instructions are rendered elegantly below the main score counter)

♿ Accessibility:

• Enhanced the #score element with ARIA live region attributes to ensure that users using screen readers hear real-time updates of the score seamlessly without repetition of static text.

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PR created automatically by Jules for task 8767642302095596995 started by @EiJackGH

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