🎨 Palette: Semantic Navigation & Accessibility Improvements

[ISTEC-FOR340]

This PR improves the accessibility and semantic structure of the MySketches landing page and sub-projects.

💡 What

• Converted non-semantic project cards (div with onclick) to semantic <a> tags.
• Converted "Back" buttons in project pages to semantic <a> links.
• Added high-contrast focus rings and mirrored hover transforms using :focus-visible for all interactive elements.
• Removed redundant JavaScript navigation logic.

🎯 Why

Semantic HTML provides native accessibility features like correct tab order and screen reader support without extra logic. Explicit focus states are essential for users who navigate via keyboard.

♿ Accessibility

• Improved keyboard navigation flow.
• Added clear visual focus indicators.
• Added descriptive aria-label to navigation links.
• Ensured correct language metadata (lang="en") for screen readers.

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PR created automatically by Jules for task 3124465789919759434 started by @ISTEC-FOR340

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