🎨 Palette: Improve GameCard accessibility and keyboard navigation

[Gamepulse]

This PR improves the accessibility and micro-UX of the GameCard component.

💡 What

• Added role="button", tabIndex={0}, and aria-label to the GameCard container.
• Implemented onKeyDown to allow navigating to game details using the keyboard (Enter/Space).
• Converted interactive <span> tags for genres, modes, and status badges into semantic <button type="button"> elements.
• Added focus-visible:ring-2 focus indicators for better visibility during keyboard navigation.
• Fixed a bug where the outer role="button" would block card clicks by updating the target.closest logic.
• Cleaned up an unused variable in GameScreenshotsCarousel.tsx that was causing a build failure.

🎯 Why

• The library view was not fully keyboard-navigable.
• Semantic HTML (buttons) provides better native support for screen readers and keyboard interactions than spans with roles.
• Consistent focus states are essential for accessibility.

♿ Accessibility

• Full keyboard support for game cards and their internal filters.
• Proper ARIA roles and labels for all interactive elements.
• Clear focus indicators.

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PR created automatically by Jules for task 2343183734902612041 started by @Gamepulse

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