🎨 Palette: Make category rows fully clickable and accessible

[acebytes]

💡 What
Wrapped the HStack in CategoryRow.swift with a Button to increase the hit area. Applied .contentShape(Rectangle()) so the row is fully interactive. Combined the inner text elements for screen readers.

🎯 Why
Previously, only the small checkbox icon was clickable. This made it difficult for users to interact with the list rows. Wrapping the entire row in a button provides a significantly better hit target and conforms to standard interaction paradigms.

📸 Before/After
Before: Clicking the empty space or text of a row did nothing.
After: Clicking anywhere in the row toggles the checkbox selection.

♿ Accessibility
Combined the internal UI components of each row using .accessibilityElement(children: .combine) to produce a single VoiceOver element. Furthermore, .accessibilityAddTraits(result.isSelected ? [.isSelected] : []) explicitly surfaces the selected state to assistive technologies.

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PR created automatically by Jules for task 15174302763953371544 started by @acebytes

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