🎨 Palette: Improve list row accessibility and hit targets

[acebytes]

💡 What: Wrapped list rows in Button with contentShape, and combined accessibility elements.
🎯 Why: Checkbox-only buttons create poor hit targets and VoiceOver reads row contents fragmentally.
📸 Before/After: Rows are now fully clickable and highlighted correctly.
♻️ Accessibility: Added .accessibilityElement(children: .combine) and .isSelected trait for VoiceOver users.

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PR created automatically by Jules for task 14313494041965054711 started by @acebytes

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