🎨 Palette: Add accessibility modifiers to collapsible section header

[acebytes]

💡 What: Added accessibility modifiers (.accessibilityElement(children: .combine), .accessibilityLabel, .accessibilityValue, .accessibilityHint) to the NodeModulesSection header.
🎯 Why: The custom section header mixes text and icons. Without these modifiers, VoiceOver reads each component separately, failing to convey that it functions as a single interactive element with an expandable/collapsible state.
📸 Before/After: N/A (Non-visual accessibility improvement)
♿ Accessibility: Screen reader users will now correctly hear the header as a single button, its current state (Expanded/Collapsed), and instructions on how to toggle it.

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PR created automatically by Jules for task 9702155804377750044 started by @acebytes

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