🎨 Palette: [UX improvement] Make safety checklist accessible

[dhaatrik]

💡 What: Added proper semantic attributes (role="checkbox", aria-checked) and explicit keyboard focus styling (focus-visible:ring-primary, focus-visible:ring-offset-2) to the custom interactive checklist buttons in the SafetyChecklist component.
🎯 Why: Custom form controls built with standard elements like <button> lack inherent meaning to assistive technologies. Without these attributes, screen reader users might not understand they are interacting with a checklist or what the state of each item is. Furthermore, without explicit focus styles, keyboard users struggle to navigate through the brutalist design system where default browser outlines are often suppressed or insufficient against thick borders.
📸 Before/After: The component functions exactly as before for mouse users, but keyboard navigation now clearly highlights the focused item with the application's primary accent color.
♿ Accessibility:

• Added role="checkbox" for semantic screen reader interpretation.
• Bound aria-checked={isChecked} to dynamically announce state changes.
• Added explicit keyboard focus styling for clear visual feedback during tab navigation.

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PR created automatically by Jules for task 3767621967309354006 started by @DhaatuTheGamer

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