🎨 Palette: Enhance VoiceOver accessibility for node_modules section header

[acebytes]

💡 What: Added accessibility modifiers to the node_modules section header button.
🎯 Why: To ensure VoiceOver correctly reads the custom section header button as a unified interactive element and conveys its current state (Expanded/Collapsed).
📸 Before/After: Visuals remain unchanged, but VoiceOver now reads the element properly instead of individual components.
♿ Accessibility: Applied .accessibilityElement(children: .combine), .accessibilityLabel, .accessibilityValue, and .accessibilityHint to the section header button.

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PR created automatically by Jules for task 11428583181124861714 started by @acebytes

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